You're welcome my Friend......and...I appreciate your kind words. As for these Thermoquad videos, I fumbled my way through trying to figure out what does what, trying to make them run and respond correctly, and being the head-scratcher that I am, I figured that I should share what I have learned over countless hours of tinkering, adjusting, reading about, messing with...well, you know!...lol...Cars are just one of my hobbies. If one is interested, one will learn! Take care Bud!
Thank you so much for posting these videos. There isn't much out there on TQs and you have done a real service for people working on them. I had a problem with mine bogging, but only after it had warmed up to full temperature. I finally figured out that the piston was binding in the hole after it heated up. A little lube on it and it moves freely and runs like a scalded cat. It looks like they were originally coated with maybe teflon, but that wears off over time.
I will do the accelerator pump test sometime today. I've been watching your responses and have been waiting for you to finish before I replied. I had done some more tinkering yesterday after I had made my initial post. I had richened the metering rods even more than I'd had when it backfired. So far, no backfire and it runs much better than it did before. Bog is almost completely gone. As far as other symptoms, it starts and idles great, accelerates fine once you get past the bog. ...cont....
Greetings...Steve F. ……...You're welcome, and, thanks for watching...…...Here are some things, that you should be aware of/consider...…….When it comes to the setting up/adjustments, on a Thermoquad carburetor, then, it's..."very important"...to make those settings/adjustments in the..."correct sequence"...(order of doing them), or, the Thermoquad, won't work very well at all...…….If your TQ (ThermoQuad), has those nitrophyl floats (looks, kinda like, black plastic), then, they can sometimes absorb gasoline, and then, start to sink, which will usually make for, a really, rich running TQ, most times...…….There are usually, Brass (metal) floats made, for the TQ carb also, which will usually last a lot longer...…….Buy and install, a new...choke pull-off...(looks like a little space ship...lol), because, the rubber-like diaphragm, that's hidden inside of it, will usually dry up/harden, with heat and age, and will sometimes get stuck, and, "it" has two functions, as in, it opens the choke plate, a small amount, upon start-up, as well as, it, controls/regulates, the secondary air door's opening rate (very important...!!!)………..Sometimes, the TQ will run a bit lean (of an air/fuel ratio), when putting, about 10% ethanol gasoline, in the gas tank, and if so, then, the primary (and maybe, the secondary) fuel jets too, might have to be increased in size, a bit...……..I had a lean condition, where, the engine would "surge" (car, was kinda lurching, back and forth), while just going city speed, while having the gas pedal held steady (probably because, the factory TQ carb, was calibrated/jetted, for 100% gasoline...and, not for, the 10% ethanol/gas-em-ah-haul stuff...!!!...lol)………..As I recall, my primary fuel jets, were factory/original .095" (ninety-five thousandths of an inch, orifice/hole size), and, I ended up, having to use .104" (one hundred and four thousandths of and inch), just to get rid of, that lean surging, that I was having, at that particular time...……Look up...Vaanths Thermoquad guide...on the internet, because, the guy that wrote/compiled it, did a fantastic job, to say the least...…...Good luck with your TQ rebuild, and...….till next time...…..Be Safe, take care, and have a good one.
@@RockysRoadshow I followed the adjustment sequence in my trucks factory service manual. Installed it today, and it started quickly. I still need to do the on truck adjustments. I will then see how it drives. Did back fire when I revved it. I will look for vacuum leaks. The primary jets are .096 , .098 is what they came with from the factory. So, just a little leaner than stock. I'm at 1800 feet elevation, so I think that would be just about what I need. But if the ethanol in the gas is a problem, I will adjust. I will use the spark plug color as a guide. Thank you for the advice.
Thanks for your kind gesture Philip....I plan on making many more Thermoquad videos in the not too distant future....If, and when you get a Thermoquad (the early 70's ones, possibly late 60's as well, as they didn't have all of that Smog Junk) set-up, and running like they were intended to, then, you would be a very "Happy Camper" indeed!....As I ponder some thoughts, thinking about how simple, and perhaps complete that I can make these Thermoquad videos, all the better....Take care my Friend.
Rocky, Thanks. I really appreciate your videos. Carbs are not my specialty and therefore the are a little scary to get inside, but I am not going there. Just fine tuning. Your videos are very easy to understand. I cannot say enough good about them. I just had foot surgery and therefore I cannot push in the clutch. So, if you do not hear from me for a while-that is why. Cannot get to work on car. :) Numbers are a little hard to read, but here they are. Top is 6548S and the bottom number is 35776. I believe that 35776 is the S/N and the other is model. I purchased it rebuilt and runs fine, with the exception of running rich. I worked on the idle mixture and they were six turns out. I got them down to 2 turns and it is a lot better. Therefore, with the idles being so far out, I can safely assume that the Metering may be off. Worth checking. Carb is vacuum choke. Engine is 340 bored at least 30 over. That old of engine, you know that it is hard to tell. It has been stroked and therefore we figure it is running around 11.25 compression. Cam is a 506 lift. Manual 4 speed transmission. Yes, it does do the Cha-Chugg routine. Thanks again. P.S: I have no emissions requirements here. I just want to get it dialed in better.
Mc Ca Greetings Mc Ca....You're welcome, and, Thanks, for Your Outstanding, and well appreciated comment, that You indicated, about my Thermoquad Videos, my Friend.The Thermoquad carburetor Number, that is Most Useful, for, looking up the Specifications for it, as well as, telling the Parts Guy/Gal, the Needed Information, so He/She will be able to provide You or Others, including myself, are those..."4-Numbers-Followed-by-the-Letter-"S".I had a look-see on..."Vaanths Thermoquad Guide"...for the "4-Numbers" & the Letter "S"...which You indicated as...6548S...I Did-Not See that...6548S...in the Listing......Maybe, it might be...6545S...(?), which happens to be the Identifying Numbers & Letter, that is Stamped on the Thermoquad carburetor, that You see in All of these Thermoquad carburetor, UA-cam Videos of mine perhaps...???Once You are fully healed, after having Your foot surgery, and are able to get around without too much difficulty, maybe, have a look-see, to actually "Verify", those..."4"-Numbers-Followed-by-the-Letter-"S"...that way, I will be able to Look-Up, the much Needed Information, which will help a very great deal...!!!Those "4"-Numbers-followed-by-the-Letter-"S", are usually "Stamped" into the "Lowest" Part of the Thermoquad carburetor, on the "Left Hand Side", at the "Rear/Back".Before I forget, there is another very important thing, that can happen, when Setting the Thermoquad's "Idle SPEED Screw" Too High (aka, clockwise, and In too much), and, besides, having that Extra Air/Fuel from the Thermoquad's "Low Speed Circuit", Added, to the Air/Fuel that is already coming from the "Idle Circuit", happens to be, how it might "Add In Additional Ignition Timing", at "Idle Speed", from the "Vacuum Advance System", if indeed, Your Distributor has a "Vacuum Canister/Unit" on it, that looks, kinda like a little Space Ship, and its Vacuum Hose, is connected, to what is known as "Ported Vacuum", that takes its "Vacuum Signal", from just "Above" the Primary Throttle Plates/Butterflies, when the Primary Throttle Plates/Butterflies are almost Fully Closed.Your Thermoquad's "Choke Pull-Off"...besides Controlling the Choke System..."ALSO"..."Controls"...the..."Opening Rate"...of Your Thermoquad's..."Secondary Air Door"...!!!...just sayin'.Now for..."Adjusting" the "2 Idle Mixture Screws", and the "Idle Speed Screw"...The "Idle SPEED Screw" that I usually use, in order to Set the "Idle SPEED", is that Screw, that is just "Above", that Big Heavy "Fast Idle Speed Screw"...Now then, when it comes to "Adjusting" the "2 Idle Mixture Screws", it's very Important, to keep "Both" of them, Turned "In or Out", about the Same Number of Turns, and Partial Turns, in order to keep "Both" Primary Throttle Venturi-ees/Throttle Bores..."BALANCED"...or, Your Thermoquad carb, might not Work/Perform as good as it's able to.Just in case, You might not already know, always remember to have Lots of Ventilation and Fresh Air, when-ever Your Engine is Running, because the Engine's Exhaust Gas is "Deadly"...!!!The first thing to consider, before starting to "Set-Up", Your Thermoquad carb's "Mixture Screws", is to "Select", what You think, would be an Acceptable "Idle Speed".Have the Engine fully warmed up to Operating Temperature, and, "Make Sure", that the "Choke" is Fully "Off", as in, the "Choke Plate" is fully "Vertical", and, the Big Heavy (it's actually a Counter-Weight) "Fast Idle Speed Screw", is All the way to the "Bottom" of it's Travel, and in No Way, is that Big Fast Idle Speed Screw, making "Any Contact" what-so-ever, with the Throttle Lever (Yes-Sir-ee-Bob, the Lever that has the fast Idle Cam steps on it...lol). As an example, I have used the "Specifications", that were found on the Vehicles "VECI" (Vehicle Emission Control Information) Label/Sticker, that is usually found in the engine compartment, on a Factory High Performance Dodge 360 Cubic Inch small block V-8 Engine, with an 850 CFM (Cubic Feet per Minute) Thermoquad carburetor, that was also equipped with that good ole A-833 4 Speed (Manual/Standard) Transmission, that was controlled with that good ole Hurst Pistol Grip Shifter, never-the-less... Then, having the Vehicle on Level Ground...all 4 Tires Chalked with Bricks, to prevent the vehicle from Moving...Emergency/Parking Brake On/Applied...With the Garage Doors OPEN, and having Lots of Ventilation and Fresh Air, I Run the Engine, in "Neutral" (it's a Manual/Standard Transmission eh!...lol), until it's at Operating Temperature, then, turn Off the Ignition, and take the Key with me...First, with Engine "Not Running", I Lightly "Seat" the 2 "Idle Mixture Screws, and place a White Chalk Mark on each of the 2 Idle Mixture Screws, at the 12-O-Clock-High Position (aka, closest to the Sky), in order to establish a "Reference Point", to make things nice-n-easy...Then, I turn Each of the 2 Idle Mixture Screws "Out" (Counter-Clockwise) from being lightly seated, "4-Full Turns"...Then, with Engine still at Operating Temperature, and, the Choke Fully Off, I Re-Start the Engine, and, being very Careful around all of the Hot and Moving Parts and Pieces, in the Engine Compartment, I Adjust the "Idle SPEED Screw", until my Tachometer (aka, Tach), is showing/displaying "850-RPM's"...I then, Adjust "Each" Of the 2 "Idle MIXTURE Screws "IN" (Clock-Wise) Equally, 1/4 (one-quarter) Turn Each time, as in, Turn In, the Left Idle Mixture Screw 1/4 Turn, then the Right Idle Mixture Screw In 1/4 Turn, and always remember to keep "Both" Idle Mixture Screws, Showing the White Chalk Mark, Pointing in the Same direction, as one another, and having the Same Number of Turns and Partial Turns as well...!!!You will Notice, that, when-ever, You are Adjusting the "Idle MIXTURE Screws", that, the "Idle SPEED" will "Change", as You do so...When the "Idle SPEED" Changes, it's just a matter to just "Re-Adjust" the "Idle SPEED Screw"..."Back To"...the, and in my case, that "850-RPM's", or, what-ever, the Engine "Idle SPEED", happens to be, that You have chosen, for "Your Engine"...!!!Seeing as how, You had mentioned, that, You Do Not have to comply with any of that Smog/Emissions Testing Stuff, just keep Adjusting Your Thermoquad Carb's..."Idle MIXTURE Screws"..."EQUALLY"...until You get to the point, of having Your Engine "IDLE", at the "FASTEST RPM's"...While Keeping Your Engine's..."IDLE SPEED"...at (in my case 850 RPM's in Neutral), or, what-ever You have chosen, or, what-ever "Your Engine" Idles "Best" at, with the "Idle SPEED Screw".When You think that, You have made the Best Adjustment/s possible, make sure, that, the..."White Chalk Marks"...On "Each" of the "2" Idle Mixture Screws..."Are Pointing In The Same Direction" (aka, as in, the Oh-Clock/Direction, that an Analogue Clock's Arm/s Do)...in order to, try and keep, "Both"..."Idle MIXTURE Screws"..."BALANCED"...!!!As I see it, Engines are some-what, just like People, in that, "They" All seem to have...Their "Own Personalities"...!!!Now that (I hope), You might have a better understanding, as to what's goin' on, and, how to make Your Thermoquad carburetor's..."Idle Mixture" and "Idle Speed"..."Adjustments/Settings"...You will be, well on Your way, to having, as I see it, a very Strong, and great performing..."High Performance and probably Larger then a 340 Cubic Inch V-8 Engine"...!!!If You care to, You can let me know, how You make out with Your Engine's Performance and Running Issues, when-ever that time comes...If You have any questions at all, just let me know......Good luck.....and......Best Wishes, for a Full Recovery, from Your Surgery.Be Safe, take care, and have a good one.
Greetings Viridityinc....Me, a Thermoquad God?....Maybe not yet, but I'm sure working on it!...lol...Thanks kindly for your "Fantastic" comment!...Since we have these things now, you know, the Internet, and UA-cam, I can, and will be able to help you out with "Tuning" your Thermoquad...Just let me know what you're driving, engine, modifications (if any), and the model of your Thermoquad (Rebuild it for best tune-ability)...Future Thermoquad videos will show tuning as well...Take care my Friend
Greetings once again, William Ruescher....Hopefully, if and when you get that one plugged (or, semi-plugged) nozzle on your accelerator pump nozzle cluster, where one a good day, both nozzles (little tubes), discharge that much needed "Fuel-Stream" to prevent your Pick-em-up-Truck from stumbling from a stand-still, You will become a "Happy-Camper" once again....You can try the following "Cures" (that's if you haven't already fixed the problem, that is)....(con't)
...make sure that your Pick-em-up-Truck is in Park (or in gear if it's a manual transmission), and the parking/emergency brake is on, and the tires are blocked, and your vehicle is on level ground...Then, remove your air cleaner housings lid, and set it aside...Now, with one hand, push open the Choke Plate until it is fully open, and hold it there (Engine Not Running!!!)....With the other hand, move the Thermoquads gas pedal lever (its the one that the gas pedal cable is attached to)....(con't)
...now that you have that Squirter Cluster in custody, clean the passages with fishing line, and some carb cleaner (Wear Safety Glasses, and do it Outside of your House!!!)....If you have compressed air, you can use that to force the crud out as well....You might put a few drops of carb cleaner down into where the check valve (Needle) is residing, before you re-install the Squirter Cluster as well....Make sure that the little gasket is still in good condition or install a New one....(con't)
Howdy! I've got a 76 Dodge D200 pickup with the 400ci V8. The issue I'm having is an off idle bog if you don't apply throttle slowly. I richened it up via the metering rods but after a short while it backfired through the carb. So I was wondering if it's a metering adjustment, some sort of internal carb failure, or even a vacuum advance issue. Thanks for any responses!
...make sure that you Manually push the Fast Idle Screw down, to the bottom, so that is off of all the fast idle Cams Steps!....If you don't, then, your primary throttle plates will be open a bit!...(Also remember to mark and record the setting that you had on the curb idle screw or solenoid, so you can re-instate the original idle speed setting later)...Once you have the primary throttle plates 100% Closed, then, stuff some clean paper towel into the primary throttle bores for safety...(con't)
...once the previous mentioned preparation has been completed, then, all you have to do, is, remove the Squirter Cluster (just a plain screwdriver is needed for that one screw on top)....Then, with a pair of needle nose pliers, just pull straight up, and, the screw, squirter cluster, and the gasket, should now be in your hand (hopefully)...."Warning!", there is also a little check valve (NEEDLE) hiding down inside there!....It should stay there (because of Earths Gravity)....(con't)
...make sure that you move the gas pedal lever on the Thermoquad through its full travel, meaning, from idle, to wide open throttle, and repeat this a few times, while looking down into the 2 front throttle bores (primaries)....(and of course, Engine Not Running!!!)....You should be seeing 2 steady, and full streams of gasoline coming out of both of those small Nozzles that are located between those 2 front (primary) throttle bores....Weak streams = BOG from a stop with normal driving...(con't)
Alright, just tested the accelerator pump, it appears that the pump itself is working, however the jet on the left primary (you're facing the carb) is clogged a bit. Jet on the right side is nice and steady.
...I'll start with a common item, when it comes to accelerating from a stop....To me, it sounds like your Accelerator-Pump-Plungers-Seal/Cup may be worn out, or, something in that circuit is plugged up, or stuck....To check the Accelerator Pump system, try this....With your Engine Cold, Start your engine and let it run for about a minute, then, shut it off, and take out your ignition Key (so someone can't start your engine while you are under the hood!)....This fills your float bowls....(con't)
Greetings...kd6tas...……You're welcome, and, thanks for watching...…….There's some really, really good information, about the Thermoquad carburetor, on an internet webpage, and hopefully, it is still up and running...…..Just search for...Vaanths Thermoquad Guide...……..Good luck, and......till next time...…..Be Safe, take care, and have a good one.
Greetings...Wesley Markham.........Thanks for watching..........Before I forget, try this.........With the engine fully warmed up to operating temperature, do a very gradual, slow acceleration, from a stop, on a quiet/no traffic street............If it accelerates smoothly (and normally), under that, shall we say, preliminary road test, then, here are two things, that come to mind, as to that (not so wanted) lean bog..........I'll assume, that, your 360 V-8 engine has a Carter Thermoquad 4 barrel carb on top of it (and, if not, you can let me know, what carb it really is...thanks)...........First thing, is, is that it might be the "Accelerator Pump", that's supposed to squirt a stream of raw gasoline (kinda like, a little toy/water squirt gun does) into each primary throttle bore of the carburetor, when-ever your foot presses down on the gas pedal (supposed to squirt quite strongly, when you mash the gas pedal, all the way down in a hurry), and here's why...........When the carb's throttle plates/butterflies, open very quickly, the Air (same stuff that we breathe...lol), will respond/move really quickly, though those (opened in a hurry, and quite wide open) throttle plates/butterflies & throttle bores, where-as (and, as I like to say, as in), the gasoline, that comes out of the nozzles, in the carb's venturi area (that be, usually where the narrowest part of the carb's throat, or opening is), is, well, a kinda "Slow-Poke", and can't respond, and flow, as quickly as the Air is able to...........So, if the Accelerator Pump..."is-not"...squirting enough (raw) gasoline, to mix with that (super fast responding) Air, then, a "lean bog" (acceleration-wise), it will probably be, I be thinkin'...........It's easy enough, to check its function, visually, alright..........With the engine "cold", and "not running", just remove the air cleaner lid, or, what-ever is sitting on top of the carburetor, then, if need be, hold the choke plate (flap) open with one hand, then, with the other hand, operate the throttle lever/bracket, through its full range of travel, and, be "watching", to see (if in fact), that, there are "2 Solid Streams" of gasoline (1 stream for each primary throttle bore)...........If either, one, or both "streams", are some-what "Spitting", then, that's a pretty good clue, that, the Accelerator Pump, "is not" working, as good as it should be, oh, and, gotta make sure, that, the Float Bowls, have plenty of gasoline in them, or, if not, then that, in itself, can cause, the same kind of "Spitting" behaviour, just so Ya know............The other "thing", that can also cause a lean, type of (aggressive?) acceleration bog, is that Secondary Air Valve, torsional (twisting motion) "Wind-Up Spring" Adjustment (I believe that I made a UA-cam video about that item as well)...........If the Wind-Up Spring adjustment is too weak, then, the secondary Air Valve, will probably start opening, quicker than it should be............Then, there was when, I had, a, shall we say, "Rich" acceleration Bog, some years ago, where the Choke Pull-Off (that controls the Choke actuation, as well as, the secondary Air Door "opening rate"), was either sticking/got stuck, or moved too slowly, causing that Secondary Air Valve, to open way too "S-l-o-w-l-y" (or maybe, not-at-all...???), and the engine popped, would not go anywhere, in any kinda hurry, and sounded, very, very sick...........The "choke pull-off", is that little space ship lookin' thing, on the side of the Thermoquad carb, and, it's easy to check (some-what) as well..........With engine "cold" and "not running", remove that short, rubber looking hose, from the pipe, that's part of that choke pull-off, then, just push that flat metal bar, straight in, until it stops, then, place a finger or thumb, on the end of that little metal pipe, to plug the little hole, that's in the end of it.............Now, remove your hand, from that flat metal bar, and "Watch" it...........The flat metal bar, might come out, just a tiny bit, and then, it should stop, and stay there, and, if not, then, the rubber-like diaphragm, that's inside of it, might have a crack/air leak in it............Next test (yes-Sir-ee-Bob, there's another one...lol)...and that, is to, remove your finger or thumb quickly, from that little pipe, and "Watch"............That small flat metal bar, should come out slowly and smoothly, and, at a very constant speed, and pretty much, in a straight line as well...........If it does the "herky jerky", then, it's time for a new one...........Also, ignition system problems, can act kinda goofy sometimes, so, keep that in mind as well..........If you care to, you can let me know, how it's going...thanks.............Good luck, and........till next time.......Be Safe, take care, and have a good one.
...try this first...Find a small diameter piece of Fishing Line, and see if you can Probe the plugged nozzle with it, as this might dislodge, or, open up the clogged tube...You might also put a small amount of Carburetor Cleaner or some other type of solvent that is strong enough to dissolve, what I think is dried up gasoline residue (cuz, when gasoline evaporates, it usually leaves behind a brownish, dried glue like substance, and perhaps, this is your Culprit?)..Maybe do both tubes?...(con't)
I made an adjustment to that screw on the back, after the butterfly touched the top, I turned it 1 and 1/2 turns and locked it with the key, the butterfly accelerated quickly without a filter, the car stopped, but with a filter, the car stopped The throttles behind the carburetor didn't come in, a friend who only comes in when driving on roads?
...make sure that, after you put the "Clean" gasket, squirter cluster, and tighten the screw on top of the squirter cluster, that "ALL" Parts, pieces, bits, crud, and don't forget to remove "ALL" of that protective paper towel that you put in the primary throttle bores, or, Engine Damage Will be the Result!!!....Then, re-set your Idle Speed Screw, or Idle Speed Solenoid to where it was, just before you started all of this, to get your Engine idling back where it was before..Good Luck..Bye 4 now
...the paper towel needs to be placed below the level of the Squirter Cluster, to keep the small parts from dropping into your intake manifold and engine!....Note, if any small parts get down past your Thermoquad, then You have to remove your Thermoquad from the intake manifold, and remove any, and all parts, bits, and pieces that don't belong there, or, the small stuff will get inhaled by your Engine, and there will be "Catastrophic-Consequences!!!", meaning, one Destroyed Engine!....(con't)
I realize i'm commenting on a very old vid but just taking a chance....Thank You for the Thermoquad series. I'm retired auto tech but new to Thermoquads , I have a bogging problemi & 'm seeking your experienced advice. This Thermo is 1975 original that was rebuilt by someone recently,but before my possession & these are the symptoms....#1 Hard starting, #2 Upon starting all the way through operating temp the engine idles great but refuses to stay running or cruising when pedal is pushed any amount off of idle.(No Primary Circuit activity at all,imo). Accelerator pump pumps good strong streams. #3 Typical manner of getting this 1965 Coronet 440 from "A" to "B" in this condition is to let out the clutch very gradually from stopped, while "pumping" the gas pedal furiously. Upon reaching high gear this way i have to KEEP PUMPING just to MAINTAIN speed ?!? PS The secondaries,(WOT), work great....if you want to accelerate all the time,lol. I've made the Metering Rod adjustment contained in this fine video but had no effect. Thanks in advance.
Greetings...Shane Williams.........You're welcome, and, thanks for watching........Sure sounds like, the primary circuit/s might be dirty or plugged up........I had a TQ, that, just stopped idling, when I stopped at a red light (not fun, with an A-833 4-speed transmission, along with a clutch pedal, just like you...lol).......All I did to fix that, was to remove the two idle mixture screws, then took a length of clear neoprene/fish tank, plastic tubing, and blew as hard as I could, into those two idle mixture, screw threaded holes, then, re-installed & re-set the idle mixture screws, and never had that problem again...yip-ee...lol........Float level setting, might be too low on your TQ (I recall, a one inch setting, with the nitrophyl (looks like black plastic) type of float (check the specifications for your own TQ)........If it were me, I'd get a rebuild kit, and make sure it was rebuilt/set up correctly..........Use "Brass" floats (nitrophyl/black plastic-like floats, will sometimes turn into sponges, causing the float to sink).......Use a "New" choke pull-off (the internal rubber-like diaphragm, inside of an older/used choke pull-off, will get dried out & stiff, possibly cracked...it might work ok for choke actuation, but, not so good at all, for regulating the opening rate, for the secondary air door...I had one that was sticking a bit, and, the engine popped and ran like...{choose your own word}...lol)...when I tried to go...pedal-to-the-metal........I use various diameters of fishing line, to clean out the tiny fuel and air passages, along with some carb cleaner, in the TQ's air horn/top aluminum section (if using guitar string/wire, then, make sure to file off the sharp jagged end, into a rounded shape, so it doesn't act like a cutting tool, which will score, and probably enlarge the passageway, that it was fed into, just sayin'..........So then, after everything is super clean, including, all of those tiny passageways, then, the most important/crucial part, of the TQ's rebuild, is to...make sure that, all of the adjustments and settings are done in the..."Correct Sequence"...!!!...(even, some so called carb experts, are not aware of this, at all, when it comes to having a TQ, to work, as good, as it was designed to perform).........Fear not, my friend, because, the paper instructions, that come inside of the rebuild kit, will show you the ..."Correct Sequence" (that be, the order in which to perform the adjustment and settings)...oh, and, I had very good luck, with the Hygrade brand of TQ rebuild kit.........Also, the really thick factory gasket, that goes between the bottom of the TQ and the intake manifold, for the mid-1970's Dodge V-8 engines, looked kinda like, two, very thick pieces of leather, that appeared to be stapled together (very small, industrial quality staples, at that, and, the total thickness, was no less than, oh, about 3/8-ths of an inch, there-abouts.........So yeah, no telling what the last guy did, with your TQ, it's anybody's guess, at best, well, unless the guy, truely, really did know, what he was doing, that is..........I had to re-jet a TQ a bit richer, primary, fuel jet-wise, because of that, about 10% ethanol (alcohol), which I like to call...Gas-em-ah-haul...lol........Keep in mind, that, the TQ's that were made, way back when, were "calibrated", when, there use-tah-be...100% Gasoline (with no ethanol in it).........The more % of ethanol, that's in the gasoline, then usually, the larger, that, the fuel jets have to be, for the engine to run right (less BTU's in ethanol, specific gravity differences as well, possibly).........Check your fuel pump volume and pressure (too low on each count, possibly...???)........Fuel and air filter clean...???........Ignition system, ignition timing, spark plugs, etc. ok...???........Over time, I've found some really unexpected culprits, fooling me, until I started with the simple things first (I still recall, that, the carburetor will usually get blamed first, probably because it's just sitting there, just staring at you...!!!...lol).........So, check out all the simple things, and Ya might find the unexpected, when Ya least expect it, so now...go inspect...lol........If Ya need anymore help at all, or, Ya get-er-fixed, then, just give me a shout.........If all else fails, in getting your TQ to behave properly, then, maybe check out...Demon's...Street Demon Carburetor...that is a really good street carburetor, and, it has quite a few of the TQ's features, and they even have a model, that has that black thermoplastic/space-age center section too...........Two sizes as I recall...625 CFM...???...and...750 CFM...???..........Good luck, and......till next time......Be Safe, take care, and have a good one.
@@RockysRoadshow Thanks a bunch for all the detailed instruction. The carbs' off the car & i will proceed with the things you have outlined. Some things i've forgotten & some you mention are new to me. Even at my age i still love to learn. Now, All the other engine systems have been gone thru by me & eliminated *Except* checking for fuel pump volume. Glad you mentioned it, I will do that for certain. This gonna take me a bit but i'll let you know how it's going. Thanks again for sharing your knowledge.
I agree with egrand1508. Thermoquads are either loved or hated and therefore there is not much info. Mine is rebuilt and is off of a 1974 440. It is now on a 340 with a manual. It has a 504 lift cam with approximately 11.25 compresion and is bored over. It runs good, but has always ran rich. I mean it stinks and stinks up the garage. :( I I adjusted the idle circuit jets to base plus have turn. So, screwed them in lightly and backed out CCW two screws. This has helped tremendously. Smell and performance. Now I am wondering about the metering. I have been doing this by sight, hearing and smell. I am going to consider getting an analyzer to get more precise. My question to you is, with the modifications-where do you recoomend that I start or finish? This is not a daily driver, it is a hot rod. I think that some fine turing willl really help. Thanks
Mc Ca Greetings Mc Ca....Thanks for watching, and for, Your comment, and question/s as well................................................I will, do what I can, to help You out, with Your Carter Thermoquad Four Barrel Carburetor's Operation and Performance issues...............................................So then, let's start with the...Actual Thermoquad..."Serial Number"...shall we..........................................You will "Find" the "4 Digit Number", that is usually followed by the Letter..."S"..."Stamped" into the "Lower Left" and at the "Bottom", at the "Rear" (throttle body or aluminum casting)...............................................If, and when, You let me know, what the Serial Number of Your Thermoquad carburetor, happens to be, the More, that I will able to help You out...........................................There were, So Many "Different" Thermoquad Carburetors made, over the Years, that they were Manufactured/Produced, like You wouldn't believe...!!!...............................................It seems, that, each and every Thermoquad, was Designed/Calibrated, for not only Each Engine Size, and then some, but also, there were "Differences" in the Engineering/Calibration, for "Automatic" and "Manual" (standard transmission, with the Clutch Pedal).................................................Seeing as how, You were saying, that You had a "340" with a "Manual"...???........................................I'm thinkin', that "Manual", that You indicated, might be a..."4-Speed-Manual-Transmission"...perhaps...???......................................Maybe even an..."A-833-4-Speed-Manual-Transmission"...perhaps/maybe...???....................................Even..."If"...the "Thermoquad" that You have currently Installed on Your 340, happens to be Originally Designed/Calibrated for an "Automatic Transmission", I'm pretty sure, that, we should be able to make it..."Smoke-the-Tires"...without too much difficulty, once that good ole Thermoquad Carb, gets sorted out............................................Now then, there are Numerous (aka, Many) Things, that can cause a "Rich-Running" Thermoquad alright.............................................Maybe, I'll start with...let's "Assume", that Your Thermoquad carburetor was "Rebuilt-100%-Correct"...then, as I see it, the very "First" thing, that I Noticed, in Your Comment, is Your..."Camshaft"...with that "502-Lift"...........................................While I'm at it, was Your 340's Camshaft "Lift", Measured at the Camshaft's "Lobe/s", or was it "Total Valve Lift"...??? (just wonderin', that's all)........................................When-ever a "Camshaft", that "Sounds" like it's going..."Cha-Chugg"..."Cha-Chugg"..."Cha-Chugg"...while the Engine is fully warmed up, and just "Idling", like Most, quite..."Aggressive Camshafts"...usually Do, as Opposed to a "Factory Stock" Camshafts that, shall we say..."Behaves Itself"...as in, not so much..."Cha-Chugging"...has me thinkin' the following...................................................When-ever a, shall we say..."Performance Camshaft"...is Installed in an Engine, that has..."Quite-a-bit"...or..."Lots"...of..."Overlap"...in its..."Design/Manufacture"...then, it's usually the...Additional "Overlap" (over and above that, of a Factory Stock Camshaft), that usually has a Person/Mechanic..."Adjust" the Idle "SPEED" Screw "Clockwise"...Way Too Much, in order to keep the Engine, with that "Lots of Camshaft Overlap" from..."Stalling", which is What, usually "Causes", in many cases, that..."Eye-Watering-and-Way-Too-Rich-Running-Engine...!!!...................................................Please, let me explain, what's "Goin' On".............................................Once the Engine, with that Camshaft, that has that "Large Amount of Overlap" is fully warmed up to Operating Temperature, and, when-ever You Adjust the "Idle Speed"...Higher...with the "Idle-SPEED-Screw", or "Solenoid", if so equipped, then, the "Primary Throttle Plates/Butterflies", will then be "Opened Up Too Much", which will Result in, Enough..."Air Flow"...through the "2" Primary "Venturi-ees/Throttle Bores", that, will then, start to Allow/Make the, shall we say...Primary "Low Speed Circuit" (1 Nozzle, as seen in Each Primary Venturi/Throttle Bores), in the Thermoquad, start to, and keep "Flowing", an "Air/Fuel Mixture", that is actually being..."Added"...to the Already..."Flowing"..."Air/Fuel Mixture"...from the..."Idle Circuit"...that is being Controlled with the "2-Idle Mixture Screws", in the Thermoquad, at "Idle Speed", which is what usually Causes that...Way Too Rich...and...Wasting Gasoline Scenario, that nobody really wants...!!!..............................................Thermoquad carburetors, as I see it, and maybe with the exception of something like a "Competition Thermoquad" carburetor, were Only intended, and Engineered/Calibrated, for, the Engines that were Installed in Vehicles, at the "Factory", that, for the most part..."Did Not"...have Engines, that had..."Very High Amounts of Camshaft Overlap"...thus, the reason, that, the good ole Thermoquad carburetor..."Will Not"...Operate Properly..."Until"...something is done, to, get those..."2-Primary Throttle Plates/Butterflies"..."Closed Down"...Close, to where they usually are/should be, when a Thermoquad carburetor is "Installed" on a somewhat "Factory Engine & Factory Camshaft".............................................When-ever an Engine is fully warmed up to Operating Temperature, and, is equipped with a Thermoquad carburetor, the "Only"..."Air/Fuel Mixture"...that the Engine should be "Inhaling" through the Intake Manifold, should..."Only"...be coming out of the Thermoquad's..."Idle Circuit" (that would be, the Air/Fuel Circuit, that the "2-Idle Mixture Screws Control), in order to..."Transition" (aka, make its way), "Properly", up to, and through the Thermoquad's..."Low Speed Circuit"...Properly, so the Thermoquad carburetor, will be able to, keep the "Air/Fuel Mixture", at the Proper "Air/Fuel Ratio", that the Thermoquad carburetor was Designed/Calibrated to "Feed/Administer", to the Engine in question.......................................What the "Old School Guys", used to do, to, shall we say..."Correct"...this Problem, of having the Thermoquad's..."Primary Low Speed Circuit"..."Feeding"...the..."Extra and Not Wanted"...Air/Fuel Mixture...when the Engine was fully warmed up to Operating Temperature and "Idling", was to actually..."Drill" a Small Hole, in Each of the..."2- Primary Throttle Plates/Butterflies"...somewhere "Between", the "Transition Slot" (nearest the Front of the Thermoquad carb), and the "Throttle Shaft", in order to "Provide" some "Additional"..."By-Pass"..."Air"...so that, the..."Idle-SPEED-Screw"...can be Adjusted Properly, so, the Thermoquad's..."Low Speed Circuit"..."Does Not" Feed, any Additional, and Not Wanted..."Air/Fuel Mixture"...to the Engine, while it is Only at..."Idle Speed"...!!!.......................................Some of the Performance Carburetors, that are sold these days, actually have, a, shall we say..."Idle Air By-Pass"...Feature/Adjustment in/on them, to make sure, that the "Throttle Plates/Butterflies" are in the "Correct and Needed"...Position at Idle Speed..so, the Carburetor will Work Correctly, at all Engine Speeds and Loads..................................................Could also be, that, One, or Both, of Your Thermoquad's Carburetor..."Floats", especially, if they are made out of that..."Nitrophyl" (aka, looks like black plastic) material, that may have, or are starting to Absorb Gasoline, which will cause them to start "Sinking", which will also cause a Rich Running Thermoquad Carb as well...!!!............................................I always like to actually..."See"..the "Inside" of a Thermoquad carburetor, that way, I can Verify, the Float Settings...the Sizes of the "Primary and Secondary Jets" that are Installed....the Condition, of the Accelerator Pump Seal/Cup...any Damage...just how much Debris/Crud/Yuck-ees, that might be Hiding in there...etc.)............................................So then, if Your 340's Engine, happens to have a Camshaft with "Lots-of-Overlap", then, You will have to, find a way, to get some "Additional By-Pass Air" Past the Throttle Plates/Butterflies, so the Primary "Slow Speed Circuit"..."Does Not"...Keep Feeding, all of that Extra Air/Fuel Mixture to Your Engine, while it is fully warmed up, and at "Idle Speed", or, Your Thermoquad carburetor, just won't be able to (transition) and work, like the Carter Engineers/Designers Intended them to Operate...............................................Also, some Folks, have Adjusted Their..."Ignition Timing"...in order to be able to, get the "Idle-SPEED-Screw (or Solenoid, if so equipped) "Down", close to where it should be, but, "Make Sure", that, You Fully Understand, all about..."Ignition Timing"...and its..."Effects"...on the Engine, or, there is, as I see it..."A Strong Possibility"...that..."Major Engine Damage"..."Might/Will Occur...!!!........................................Oh Yeah, if and when the Idle Speed is..."Set Correctly"...You should be able to see, once the Thermoquad is removed from the Intake Manifold, that is, and held "Upside Down"...that the "Transition Slot"...that You see, that is "Exposed/Open", just Under the Throttle Plates/Butterflies, should be about the Shape of a Little "Square" there-abouts....................................................If "Too Much" of that "Transition Slot" is Showing/Exposed" Under the Throttle Plates/Butterflies, that's tellin' me, that, by being, that much too open, has a good possibility, that the Thermoquad's..."Low Speed Circuit"...just might start..."Feeding" that "Very Unwanted and Extra" Air/Fuel Mixture at "Idle Speed", and also, Not wanted "Fumes" and Lack of Gas Mileage/Kilometer-age as well...!!!............................................Have You had a Look at Your Engine's "Spark Plugs" at all...???....................................If and when, You manage to get Your Thermoquad..."Dialed In"...and it gets close to, how I was able to make them Perform, and at times, with pretty good Fuel Economy as well, but Only when, I'm Not Doin', the...Pedal-to-the-Metal...what-sham-ah-call-it...lol...................................................So, I'll leave You with (all of...lol) this Information, and, if You decide to stay with Your Thermoquad, I'll be around here somewhere.............................................'Till next time...................................Be Safe, take care, and have a good one.
...if your Thermoquad passed the Accelerator Pump Stream-Squirting-Test, then, there is still trouble in Paradise....Change your Fuel Filter lately?....They can, and do plug-up occasionally, as well as a weak fuel pump, can cause a lean running condition....The Thermoquads choke pull-off diaphragm, as well as your vacuum advance diaphragm can deteriorate with heat and age....Before i go any further, let me know all of your Thermoquads symptoms....Like, does it start and cruise ok?....Take care
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
tetedemarc Greetings tetedemarc...I saw that "Drag Racing"..."Station Wagon"..."UA-cam Video"...of Yours, and the "Engine", sure Sounded..."Very Impressive"...alright...!!!...........................I did leave a "Comment", under that UA-cam "Video of Yours"...................Till next time...........Be Safe, take care, and have a good one.
Greetings William Ruescher....(jumping in my "Time-Machine", and heading back to 1976)....First off, I'd like to say, if your Thermoquad hasn't been re-built at all lately, and your Thermoquad has never been removed from your intake manifold, then, more then likely, some of your Thermoquads working parts may have either deteriorated or are just plain worn out....There are many culprits that may be causing your Pick-em-up-trucks poor running issues....(con't)
Hello Sulivanyk....I'm sorry, but I don't speak your Language....I only speak English....Maybe you can find someone where you live that can "Translate" your Language into English, and English, back into your Language....I'm always willing to help people, whenever possible....So, if you can ask questions in English, I will be able to help you with almost any questions that you may have....Take care my Friend, and have a nice day.
...make sure that you Manually push the Fast Idle Screw down, to the bottom, so that is off of all the fast idle Cams Steps!....If you don't, then, your primary throttle plates will be open a bit!...(Also remember to mark and record the setting that you had on the curb idle screw or solenoid, so you can re-instate the original idle speed setting later)...Once you have the primary throttle plates 100% Closed, then, stuff some clean paper towel into the primary throttle bores for safety...(con't)
...try this first...Find a small diameter piece of Fishing Line, and see if you can Probe the plugged nozzle with it, as this might dislodge, or, open up the clogged tube...You might also put a small amount of Carburetor Cleaner or some other type of solvent that is strong enough to dissolve, what I think is dried up gasoline residue (cuz, when gasoline evaporates, it usually leaves behind a brownish, dried glue like substance, and perhaps, this is your Culprit?)..Maybe do both tubes?...(con't)
...make sure that, after you put the "Clean" gasket, squirter cluster, and tighten the screw on top of the squirter cluster, that "ALL" Parts, pieces, bits, crud, and don't forget to remove "ALL" of that protective paper towel that you put in the primary throttle bores, or, Engine Damage Will be the Result!!!....Then, re-set your Idle Speed Screw, or Idle Speed Solenoid to where it was, just before you started all of this, to get your Engine idling back where it was before..Good Luck..Bye 4 now
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
...make sure that you Manually push the Fast Idle Screw down, to the bottom, so that is off of all the fast idle Cams Steps!....If you don't, then, your primary throttle plates will be open a bit!...(Also remember to mark and record the setting that you had on the curb idle screw or solenoid, so you can re-instate the original idle speed setting later)...Once you have the primary throttle plates 100% Closed, then, stuff some clean paper towel into the primary throttle bores for safety...(con't)
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
You're welcome my Friend......and...I appreciate your kind words. As for these Thermoquad videos, I fumbled my way through trying to figure out what does what, trying to make them run and respond correctly, and being the head-scratcher that I am, I figured that I should share what I have learned over countless hours of tinkering, adjusting, reading about, messing with...well, you know!...lol...Cars are just one of my hobbies. If one is interested, one will learn! Take care Bud!
Thank you so much for posting these videos. There isn't much out there on TQs and you have done a real service for people working on them.
I had a problem with mine bogging, but only after it had warmed up to full temperature. I finally figured out that the piston was binding in the hole after it heated up. A little lube on it and it moves freely and runs like a scalded cat. It looks like they were originally coated with maybe teflon, but that wears off over time.
I will do the accelerator pump test sometime today. I've been watching your responses and have been waiting for you to finish before I replied. I had done some more tinkering yesterday after I had made my initial post. I had richened the metering rods even more than I'd had when it backfired. So far, no backfire and it runs much better than it did before. Bog is almost completely gone. As far as other symptoms, it starts and idles great, accelerates fine once you get past the bog. ...cont....
Thanks for all the good information. I'm rebuilding a ThermoQuad, and this is good information to have.
Greetings...Steve F. ……...You're welcome, and, thanks for watching...…...Here are some things, that you should be aware of/consider...…….When it comes to the setting up/adjustments, on a Thermoquad carburetor, then, it's..."very important"...to make those settings/adjustments in the..."correct sequence"...(order of doing them), or, the Thermoquad, won't work very well at all...…….If your TQ (ThermoQuad), has those nitrophyl floats (looks, kinda like, black plastic), then, they can sometimes absorb gasoline, and then, start to sink, which will usually make for, a really, rich running TQ, most times...…….There are usually, Brass (metal) floats made, for the TQ carb also, which will usually last a lot longer...…….Buy and install, a new...choke pull-off...(looks like a little space ship...lol), because, the rubber-like diaphragm, that's hidden inside of it, will usually dry up/harden, with heat and age, and will sometimes get stuck, and, "it" has two functions, as in, it opens the choke plate, a small amount, upon start-up, as well as, it, controls/regulates, the secondary air door's opening rate (very important...!!!)………..Sometimes, the TQ will run a bit lean (of an air/fuel ratio), when putting, about 10% ethanol gasoline, in the gas tank, and if so, then, the primary (and maybe, the secondary) fuel jets too, might have to be increased in size, a bit...……..I had a lean condition, where, the engine would "surge" (car, was kinda lurching, back and forth), while just going city speed, while having the gas pedal held steady (probably because, the factory TQ carb, was calibrated/jetted, for 100% gasoline...and, not for, the 10% ethanol/gas-em-ah-haul stuff...!!!...lol)………..As I recall, my primary fuel jets, were factory/original .095" (ninety-five thousandths of an inch, orifice/hole size), and, I ended up, having to use .104" (one hundred and four thousandths of and inch), just to get rid of, that lean surging, that I was having, at that particular time...……Look up...Vaanths Thermoquad guide...on the internet, because, the guy that wrote/compiled it, did a fantastic job, to say the least...…...Good luck with your TQ rebuild, and...….till next time...…..Be Safe, take care, and have a good one.
@@RockysRoadshow I followed the adjustment sequence in my trucks factory service manual. Installed it today, and it started quickly. I still need to do the on truck adjustments. I will then see how it drives. Did back fire when I revved it. I will look for vacuum leaks.
The primary jets are .096 , .098 is what they came with from the factory. So, just a little leaner than stock. I'm at 1800 feet elevation, so I think that would be just about what I need. But if the ethanol in the gas is a problem, I will adjust. I will use the spark plug color as a guide.
Thank you for the advice.
Thanks for your kind gesture Philip....I plan on making many more Thermoquad videos in the not too distant future....If, and when you get a Thermoquad (the early 70's ones, possibly late 60's as well, as they didn't have all of that Smog Junk) set-up, and running like they were intended to, then, you would be a very "Happy Camper" indeed!....As I ponder some thoughts, thinking about how simple, and perhaps complete that I can make these Thermoquad videos, all the better....Take care my Friend.
Just outstanding. Thank you.
Rocky,
Thanks.
I really appreciate your videos. Carbs are not my specialty and therefore the are a little scary to get inside, but I am not going there. Just fine tuning. Your videos are very easy to understand. I cannot say enough good about them.
I just had foot surgery and therefore I cannot push in the clutch. So, if you do not hear from me for a while-that is why. Cannot get to work on car. :)
Numbers are a little hard to read, but here they are. Top is 6548S and the bottom number is 35776. I believe that 35776 is the S/N and the other is model.
I purchased it rebuilt and runs fine, with the exception of running rich. I worked on the idle mixture and they were six turns out. I got them down to 2 turns and it is a lot better. Therefore, with the idles being so far out, I can safely assume that the Metering may be off. Worth checking.
Carb is vacuum choke.
Engine is 340 bored at least 30 over. That old of engine, you know that it is hard to tell. It has been stroked and therefore we figure it is running around 11.25 compression. Cam is a 506 lift. Manual 4 speed transmission. Yes, it does do the Cha-Chugg routine.
Thanks again.
P.S: I have no emissions requirements here. I just want to get it dialed in better.
Mc Ca Greetings Mc Ca....You're welcome, and, Thanks, for Your Outstanding, and well appreciated comment, that You indicated, about my Thermoquad Videos, my Friend.The Thermoquad carburetor Number, that is Most Useful, for, looking up the Specifications for it, as well as, telling the Parts Guy/Gal, the Needed Information, so He/She will be able to provide You or Others, including myself, are those..."4-Numbers-Followed-by-the-Letter-"S".I had a look-see on..."Vaanths Thermoquad Guide"...for the "4-Numbers" & the Letter "S"...which You indicated as...6548S...I Did-Not See that...6548S...in the Listing......Maybe, it might be...6545S...(?), which happens to be the Identifying Numbers & Letter, that is Stamped on the Thermoquad carburetor, that You see in All of these Thermoquad carburetor, UA-cam Videos of mine perhaps...???Once You are fully healed, after having Your foot surgery, and are able to get around without too much difficulty, maybe, have a look-see, to actually "Verify", those..."4"-Numbers-Followed-by-the-Letter-"S"...that way, I will be able to Look-Up, the much Needed Information, which will help a very great deal...!!!Those "4"-Numbers-followed-by-the-Letter-"S", are usually "Stamped" into the "Lowest" Part of the Thermoquad carburetor, on the "Left Hand Side", at the "Rear/Back".Before I forget, there is another very important thing, that can happen, when Setting the Thermoquad's "Idle SPEED Screw" Too High (aka, clockwise, and In too much), and, besides, having that Extra Air/Fuel from the Thermoquad's "Low Speed Circuit", Added, to the Air/Fuel that is already coming from the "Idle Circuit", happens to be, how it might "Add In Additional Ignition Timing", at "Idle Speed", from the "Vacuum Advance System", if indeed, Your Distributor has a "Vacuum Canister/Unit" on it, that looks, kinda like a little Space Ship, and its Vacuum Hose, is connected, to what is known as "Ported Vacuum", that takes its "Vacuum Signal", from just "Above" the Primary Throttle Plates/Butterflies, when the Primary Throttle Plates/Butterflies are almost Fully Closed.Your Thermoquad's "Choke Pull-Off"...besides Controlling the Choke System..."ALSO"..."Controls"...the..."Opening Rate"...of Your Thermoquad's..."Secondary Air Door"...!!!...just sayin'.Now for..."Adjusting" the "2 Idle Mixture Screws", and the "Idle Speed Screw"...The "Idle SPEED Screw" that I usually use, in order to Set the "Idle SPEED", is that Screw, that is just "Above", that Big Heavy "Fast Idle Speed Screw"...Now then, when it comes to "Adjusting" the "2 Idle Mixture Screws", it's very Important, to keep "Both" of them, Turned "In or Out", about the Same Number of Turns, and Partial Turns, in order to keep "Both" Primary Throttle Venturi-ees/Throttle Bores..."BALANCED"...or, Your Thermoquad carb, might not Work/Perform as good as it's able to.Just in case, You might not already know, always remember to have Lots of Ventilation and Fresh Air, when-ever Your Engine is Running, because the Engine's Exhaust Gas is "Deadly"...!!!The first thing to consider, before starting to "Set-Up", Your Thermoquad carb's "Mixture Screws", is to "Select", what You think, would be an Acceptable "Idle Speed".Have the Engine fully warmed up to Operating Temperature, and, "Make Sure", that the "Choke" is Fully "Off", as in, the "Choke Plate" is fully "Vertical", and, the Big Heavy (it's actually a Counter-Weight) "Fast Idle Speed Screw", is All the way to the "Bottom" of it's Travel, and in No Way, is that Big Fast Idle Speed Screw, making "Any Contact" what-so-ever, with the Throttle Lever (Yes-Sir-ee-Bob, the Lever that has the fast Idle Cam steps on it...lol). As an example, I have used the "Specifications", that were found on the Vehicles "VECI" (Vehicle Emission Control Information) Label/Sticker, that is usually found in the engine compartment, on a Factory High Performance Dodge 360 Cubic Inch small block V-8 Engine, with an 850 CFM (Cubic Feet per Minute) Thermoquad carburetor, that was also equipped with that good ole A-833 4 Speed (Manual/Standard) Transmission, that was controlled with that good ole Hurst Pistol Grip Shifter, never-the-less... Then, having the Vehicle on Level Ground...all 4 Tires Chalked with Bricks, to prevent the vehicle from Moving...Emergency/Parking Brake On/Applied...With the Garage Doors OPEN, and having Lots of Ventilation and Fresh Air, I Run the Engine, in "Neutral" (it's a Manual/Standard Transmission eh!...lol), until it's at Operating Temperature, then, turn Off the Ignition, and take the Key with me...First, with Engine "Not Running", I Lightly "Seat" the 2 "Idle Mixture Screws, and place a White Chalk Mark on each of the 2 Idle Mixture Screws, at the 12-O-Clock-High Position (aka, closest to the Sky), in order to establish a "Reference Point", to make things nice-n-easy...Then, I turn Each of the 2 Idle Mixture Screws "Out" (Counter-Clockwise) from being lightly seated, "4-Full Turns"...Then, with Engine still at Operating Temperature, and, the Choke Fully Off, I Re-Start the Engine, and, being very Careful around all of the Hot and Moving Parts and Pieces, in the Engine Compartment, I Adjust the "Idle SPEED Screw", until my Tachometer (aka, Tach), is showing/displaying "850-RPM's"...I then, Adjust "Each" Of the 2 "Idle MIXTURE Screws "IN" (Clock-Wise) Equally, 1/4 (one-quarter) Turn Each time, as in, Turn In, the Left Idle Mixture Screw 1/4 Turn, then the Right Idle Mixture Screw In 1/4 Turn, and always remember to keep "Both" Idle Mixture Screws, Showing the White Chalk Mark, Pointing in the Same direction, as one another, and having the Same Number of Turns and Partial Turns as well...!!!You will Notice, that, when-ever, You are Adjusting the "Idle MIXTURE Screws", that, the "Idle SPEED" will "Change", as You do so...When the "Idle SPEED" Changes, it's just a matter to just "Re-Adjust" the "Idle SPEED Screw"..."Back To"...the, and in my case, that "850-RPM's", or, what-ever, the Engine "Idle SPEED", happens to be, that You have chosen, for "Your Engine"...!!!Seeing as how, You had mentioned, that, You Do Not have to comply with any of that Smog/Emissions Testing Stuff, just keep Adjusting Your Thermoquad Carb's..."Idle MIXTURE Screws"..."EQUALLY"...until You get to the point, of having Your Engine "IDLE", at the "FASTEST RPM's"...While Keeping Your Engine's..."IDLE SPEED"...at (in my case 850 RPM's in Neutral), or, what-ever You have chosen, or, what-ever "Your Engine" Idles "Best" at, with the "Idle SPEED Screw".When You think that, You have made the Best Adjustment/s possible, make sure, that, the..."White Chalk Marks"...On "Each" of the "2" Idle Mixture Screws..."Are Pointing In The Same Direction" (aka, as in, the Oh-Clock/Direction, that an Analogue Clock's Arm/s Do)...in order to, try and keep, "Both"..."Idle MIXTURE Screws"..."BALANCED"...!!!As I see it, Engines are some-what, just like People, in that, "They" All seem to have...Their "Own Personalities"...!!!Now that (I hope), You might have a better understanding, as to what's goin' on, and, how to make Your Thermoquad carburetor's..."Idle Mixture" and "Idle Speed"..."Adjustments/Settings"...You will be, well on Your way, to having, as I see it, a very Strong, and great performing..."High Performance and probably Larger then a 340 Cubic Inch V-8 Engine"...!!!If You care to, You can let me know, how You make out with Your Engine's Performance and Running Issues, when-ever that time comes...If You have any questions at all, just let me know......Good luck.....and......Best Wishes, for a Full Recovery, from Your Surgery.Be Safe, take care, and have a good one.
You're a thermoquad God! Thank you, now if only you lived in Santa Fe, nm so you could help me tune it
Greetings Viridityinc....Me, a Thermoquad God?....Maybe not yet, but I'm sure working on it!...lol...Thanks kindly for your "Fantastic" comment!...Since we have these things now, you know, the Internet, and UA-cam, I can, and will be able to help you out with "Tuning" your Thermoquad...Just let me know what you're driving, engine, modifications (if any), and the model of your Thermoquad (Rebuild it for best tune-ability)...Future Thermoquad videos will show tuning as well...Take care my Friend
Greetings once again, William Ruescher....Hopefully, if and when you get that one plugged (or, semi-plugged) nozzle on your accelerator pump nozzle cluster, where one a good day, both nozzles (little tubes), discharge that much needed "Fuel-Stream" to prevent your Pick-em-up-Truck from stumbling from a stand-still, You will become a "Happy-Camper" once again....You can try the following "Cures" (that's if you haven't already fixed the problem, that is)....(con't)
...make sure that your Pick-em-up-Truck is in Park (or in gear if it's a manual transmission), and the parking/emergency brake is on, and the tires are blocked, and your vehicle is on level ground...Then, remove your air cleaner housings lid, and set it aside...Now, with one hand, push open the Choke Plate until it is fully open, and hold it there (Engine Not Running!!!)....With the other hand, move the Thermoquads gas pedal lever (its the one that the gas pedal cable is attached to)....(con't)
Alright, I'll try that next week. I appreciate the advice. Oh, and your replies posted multiple times. :)
...now that you have that Squirter Cluster in custody, clean the passages with fishing line, and some carb cleaner (Wear Safety Glasses, and do it Outside of your House!!!)....If you have compressed air, you can use that to force the crud out as well....You might put a few drops of carb cleaner down into where the check valve (Needle) is residing, before you re-install the Squirter Cluster as well....Make sure that the little gasket is still in good condition or install a New one....(con't)
Howdy! I've got a 76 Dodge D200 pickup with the 400ci V8. The issue I'm having is an off idle bog if you don't apply throttle slowly. I richened it up via the metering rods but after a short while it backfired through the carb. So I was wondering if it's a metering adjustment, some sort of internal carb failure, or even a vacuum advance issue. Thanks for any responses!
...make sure that you Manually push the Fast Idle Screw down, to the bottom, so that is off of all the fast idle Cams Steps!....If you don't, then, your primary throttle plates will be open a bit!...(Also remember to mark and record the setting that you had on the curb idle screw or solenoid, so you can re-instate the original idle speed setting later)...Once you have the primary throttle plates 100% Closed, then, stuff some clean paper towel into the primary throttle bores for safety...(con't)
...once the previous mentioned preparation has been completed, then, all you have to do, is, remove the Squirter Cluster (just a plain screwdriver is needed for that one screw on top)....Then, with a pair of needle nose pliers, just pull straight up, and, the screw, squirter cluster, and the gasket, should now be in your hand (hopefully)...."Warning!", there is also a little check valve (NEEDLE) hiding down inside there!....It should stay there (because of Earths Gravity)....(con't)
Hi, I had it working, I'll repeat, wouldn't there be a height from that rod to the top of the carburettor when it was working?
...make sure that you move the gas pedal lever on the Thermoquad through its full travel, meaning, from idle, to wide open throttle, and repeat this a few times, while looking down into the 2 front throttle bores (primaries)....(and of course, Engine Not Running!!!)....You should be seeing 2 steady, and full streams of gasoline coming out of both of those small Nozzles that are located between those 2 front (primary) throttle bores....Weak streams = BOG from a stop with normal driving...(con't)
Alright, just tested the accelerator pump, it appears that the pump itself is working, however the jet on the left primary (you're facing the carb) is clogged a bit. Jet on the right side is nice and steady.
...I'll start with a common item, when it comes to accelerating from a stop....To me, it sounds like your Accelerator-Pump-Plungers-Seal/Cup may be worn out, or, something in that circuit is plugged up, or stuck....To check the Accelerator Pump system, try this....With your Engine Cold, Start your engine and let it run for about a minute, then, shut it off, and take out your ignition Key (so someone can't start your engine while you are under the hood!)....This fills your float bowls....(con't)
Thanks. I've been looking around. The proper and complete procedure as you have outlined here is hard to find.
Greetings...kd6tas...……You're welcome, and, thanks for watching...…….There's some really, really good information, about the Thermoquad carburetor, on an internet webpage, and hopefully, it is still up and running...…..Just search for...Vaanths Thermoquad Guide...……..Good luck, and......till next time...…..Be Safe, take care, and have a good one.
I get a bad lean bog at first like when I floor it at low speeds. But if im already at say 50 and floor it its fine. 1979 Lil Red Express 360ci
Greetings...Wesley Markham.........Thanks for watching..........Before I forget, try this.........With the engine fully warmed up to operating temperature, do a very gradual, slow acceleration, from a stop, on a quiet/no traffic street............If it accelerates smoothly (and normally), under that, shall we say, preliminary road test, then, here are two things, that come to mind, as to that (not so wanted) lean bog..........I'll assume, that, your 360 V-8 engine has a Carter Thermoquad 4 barrel carb on top of it (and, if not, you can let me know, what carb it really is...thanks)...........First thing, is, is that it might be the "Accelerator Pump", that's supposed to squirt a stream of raw gasoline (kinda like, a little toy/water squirt gun does) into each primary throttle bore of the carburetor, when-ever your foot presses down on the gas pedal (supposed to squirt quite strongly, when you mash the gas pedal, all the way down in a hurry), and here's why...........When the carb's throttle plates/butterflies, open very quickly, the Air (same stuff that we breathe...lol), will respond/move really quickly, though those (opened in a hurry, and quite wide open) throttle plates/butterflies & throttle bores, where-as (and, as I like to say, as in), the gasoline, that comes out of the nozzles, in the carb's venturi area (that be, usually where the narrowest part of the carb's throat, or opening is), is, well, a kinda "Slow-Poke", and can't respond, and flow, as quickly as the Air is able to...........So, if the Accelerator Pump..."is-not"...squirting enough (raw) gasoline, to mix with that (super fast responding) Air, then, a "lean bog" (acceleration-wise), it will probably be, I be thinkin'...........It's easy enough, to check its function, visually, alright..........With the engine "cold", and "not running", just remove the air cleaner lid, or, what-ever is sitting on top of the carburetor, then, if need be, hold the choke plate (flap) open with one hand, then, with the other hand, operate the throttle lever/bracket, through its full range of travel, and, be "watching", to see (if in fact), that, there are "2 Solid Streams" of gasoline (1 stream for each primary throttle bore)...........If either, one, or both "streams", are some-what "Spitting", then, that's a pretty good clue, that, the Accelerator Pump, "is not" working, as good as it should be, oh, and, gotta make sure, that, the Float Bowls, have plenty of gasoline in them, or, if not, then that, in itself, can cause, the same kind of "Spitting" behaviour, just so Ya know............The other "thing", that can also cause a lean, type of (aggressive?) acceleration bog, is that Secondary Air Valve, torsional (twisting motion) "Wind-Up Spring" Adjustment (I believe that I made a UA-cam video about that item as well)...........If the Wind-Up Spring adjustment is too weak, then, the secondary Air Valve, will probably start opening, quicker than it should be............Then, there was when, I had, a, shall we say, "Rich" acceleration Bog, some years ago, where the Choke Pull-Off (that controls the Choke actuation, as well as, the secondary Air Door "opening rate"), was either sticking/got stuck, or moved too slowly, causing that Secondary Air Valve, to open way too "S-l-o-w-l-y" (or maybe, not-at-all...???), and the engine popped, would not go anywhere, in any kinda hurry, and sounded, very, very sick...........The "choke pull-off", is that little space ship lookin' thing, on the side of the Thermoquad carb, and, it's easy to check (some-what) as well..........With engine "cold" and "not running", remove that short, rubber looking hose, from the pipe, that's part of that choke pull-off, then, just push that flat metal bar, straight in, until it stops, then, place a finger or thumb, on the end of that little metal pipe, to plug the little hole, that's in the end of it.............Now, remove your hand, from that flat metal bar, and "Watch" it...........The flat metal bar, might come out, just a tiny bit, and then, it should stop, and stay there, and, if not, then, the rubber-like diaphragm, that's inside of it, might have a crack/air leak in it............Next test (yes-Sir-ee-Bob, there's another one...lol)...and that, is to, remove your finger or thumb quickly, from that little pipe, and "Watch"............That small flat metal bar, should come out slowly and smoothly, and, at a very constant speed, and pretty much, in a straight line as well...........If it does the "herky jerky", then, it's time for a new one...........Also, ignition system problems, can act kinda goofy sometimes, so, keep that in mind as well..........If you care to, you can let me know, how it's going...thanks.............Good luck, and........till next time.......Be Safe, take care, and have a good one.
...try this first...Find a small diameter piece of Fishing Line, and see if you can Probe the plugged nozzle with it, as this might dislodge, or, open up the clogged tube...You might also put a small amount of Carburetor Cleaner or some other type of solvent that is strong enough to dissolve, what I think is dried up gasoline residue (cuz, when gasoline evaporates, it usually leaves behind a brownish, dried glue like substance, and perhaps, this is your Culprit?)..Maybe do both tubes?...(con't)
I made an adjustment to that screw on the back, after the butterfly touched the top, I turned it 1 and 1/2 turns and locked it with the key, the butterfly accelerated quickly without a filter, the car stopped, but with a filter, the car stopped The throttles behind the carburetor didn't come in, a friend who only comes in when driving on roads?
...make sure that, after you put the "Clean" gasket, squirter cluster, and tighten the screw on top of the squirter cluster, that "ALL" Parts, pieces, bits, crud, and don't forget to remove "ALL" of that protective paper towel that you put in the primary throttle bores, or, Engine Damage Will be the Result!!!....Then, re-set your Idle Speed Screw, or Idle Speed Solenoid to where it was, just before you started all of this, to get your Engine idling back where it was before..Good Luck..Bye 4 now
...the paper towel needs to be placed below the level of the Squirter Cluster, to keep the small parts from dropping into your intake manifold and engine!....Note, if any small parts get down past your Thermoquad, then You have to remove your Thermoquad from the intake manifold, and remove any, and all parts, bits, and pieces that don't belong there, or, the small stuff will get inhaled by your Engine, and there will be "Catastrophic-Consequences!!!", meaning, one Destroyed Engine!....(con't)
I realize i'm commenting on a very old vid but just taking a chance....Thank You for the Thermoquad series. I'm retired auto tech but new to Thermoquads , I have a bogging problemi & 'm seeking your experienced advice. This Thermo is 1975 original that was rebuilt by someone recently,but before my possession & these are the symptoms....#1 Hard starting, #2 Upon starting all the way through operating temp the engine idles great but refuses to stay running or cruising when pedal is pushed any amount off of idle.(No Primary Circuit activity at all,imo). Accelerator pump pumps good strong streams. #3 Typical manner of getting this 1965 Coronet 440 from "A" to "B" in this condition is to let out the clutch very gradually from stopped, while "pumping" the gas pedal furiously. Upon reaching high gear this way i have to KEEP PUMPING just to MAINTAIN speed ?!? PS The secondaries,(WOT), work great....if you want to accelerate all the time,lol. I've made the Metering Rod adjustment contained in this fine video but had no effect. Thanks in advance.
Greetings...Shane Williams.........You're welcome, and, thanks for watching........Sure sounds like, the primary circuit/s might be dirty or plugged up........I had a TQ, that, just stopped idling, when I stopped at a red light (not fun, with an A-833 4-speed transmission, along with a clutch pedal, just like you...lol).......All I did to fix that, was to remove the two idle mixture screws, then took a length of clear neoprene/fish tank, plastic tubing, and blew as hard as I could, into those two idle mixture, screw threaded holes, then, re-installed & re-set the idle mixture screws, and never had that problem again...yip-ee...lol........Float level setting, might be too low on your TQ (I recall, a one inch setting, with the nitrophyl (looks like black plastic) type of float (check the specifications for your own TQ)........If it were me, I'd get a rebuild kit, and make sure it was rebuilt/set up correctly..........Use "Brass" floats (nitrophyl/black plastic-like floats, will sometimes turn into sponges, causing the float to sink).......Use a "New" choke pull-off (the internal rubber-like diaphragm, inside of an older/used choke pull-off, will get dried out & stiff, possibly cracked...it might work ok for choke actuation, but, not so good at all, for regulating the opening rate, for the secondary air door...I had one that was sticking a bit, and, the engine popped and ran like...{choose your own word}...lol)...when I tried to go...pedal-to-the-metal........I use various diameters of fishing line, to clean out the tiny fuel and air passages, along with some carb cleaner, in the TQ's air horn/top aluminum section (if using guitar string/wire, then, make sure to file off the sharp jagged end, into a rounded shape, so it doesn't act like a cutting tool, which will score, and probably enlarge the passageway, that it was fed into, just sayin'..........So then, after everything is super clean, including, all of those tiny passageways, then, the most important/crucial part, of the TQ's rebuild, is to...make sure that, all of the adjustments and settings are done in the..."Correct Sequence"...!!!...(even, some so called carb experts, are not aware of this, at all, when it comes to having a TQ, to work, as good, as it was designed to perform).........Fear not, my friend, because, the paper instructions, that come inside of the rebuild kit, will show you the ..."Correct Sequence" (that be, the order in which to perform the adjustment and settings)...oh, and, I had very good luck, with the Hygrade brand of TQ rebuild kit.........Also, the really thick factory gasket, that goes between the bottom of the TQ and the intake manifold, for the mid-1970's Dodge V-8 engines, looked kinda like, two, very thick pieces of leather, that appeared to be stapled together (very small, industrial quality staples, at that, and, the total thickness, was no less than, oh, about 3/8-ths of an inch, there-abouts.........So yeah, no telling what the last guy did, with your TQ, it's anybody's guess, at best, well, unless the guy, truely, really did know, what he was doing, that is..........I had to re-jet a TQ a bit richer, primary, fuel jet-wise, because of that, about 10% ethanol (alcohol), which I like to call...Gas-em-ah-haul...lol........Keep in mind, that, the TQ's that were made, way back when, were "calibrated", when, there use-tah-be...100% Gasoline (with no ethanol in it).........The more % of ethanol, that's in the gasoline, then usually, the larger, that, the fuel jets have to be, for the engine to run right (less BTU's in ethanol, specific gravity differences as well, possibly).........Check your fuel pump volume and pressure (too low on each count, possibly...???)........Fuel and air filter clean...???........Ignition system, ignition timing, spark plugs, etc. ok...???........Over time, I've found some really unexpected culprits, fooling me, until I started with the simple things first (I still recall, that, the carburetor will usually get blamed first, probably because it's just sitting there, just staring at you...!!!...lol).........So, check out all the simple things, and Ya might find the unexpected, when Ya least expect it, so now...go inspect...lol........If Ya need anymore help at all, or, Ya get-er-fixed, then, just give me a shout.........If all else fails, in getting your TQ to behave properly, then, maybe check out...Demon's...Street Demon Carburetor...that is a really good street carburetor, and, it has quite a few of the TQ's features, and they even have a model, that has that black thermoplastic/space-age center section too...........Two sizes as I recall...625 CFM...???...and...750 CFM...???..........Good luck, and......till next time......Be Safe, take care, and have a good one.
@@RockysRoadshow Thanks a bunch for all the detailed instruction. The carbs' off the car & i will proceed with the things you have outlined. Some things i've forgotten & some you mention are new to me. Even at my age i still love to learn. Now, All the other engine systems have been gone thru by me & eliminated *Except* checking for fuel pump volume. Glad you mentioned it, I will do that for certain. This gonna take me a bit but i'll let you know how it's going. Thanks again for sharing your knowledge.
I agree with egrand1508. Thermoquads are either loved or hated and therefore there is not much info. Mine is rebuilt and is off of a 1974 440. It is now on a 340 with a manual. It has a 504 lift cam with approximately 11.25 compresion and is bored over. It runs good, but has always ran rich. I mean it stinks and stinks up the garage. :( I I adjusted the idle circuit jets to base plus have turn. So, screwed them in lightly and backed out CCW two screws. This has helped tremendously. Smell and performance. Now I am wondering about the metering. I have been doing this by sight, hearing and smell. I am going to consider getting an analyzer to get more precise. My question to you is, with the modifications-where do you recoomend that I start or finish? This is not a daily driver, it is a hot rod. I think that some fine turing willl really help. Thanks
Mc Ca Greetings Mc Ca....Thanks for watching, and for, Your comment, and question/s as well................................................I will, do what I can, to help You out, with Your Carter Thermoquad Four Barrel Carburetor's Operation and Performance issues...............................................So then, let's start with the...Actual Thermoquad..."Serial Number"...shall we..........................................You will "Find" the "4 Digit Number", that is usually followed by the Letter..."S"..."Stamped" into the "Lower Left" and at the "Bottom", at the "Rear" (throttle body or aluminum casting)...............................................If, and when, You let me know, what the Serial Number of Your Thermoquad carburetor, happens to be, the More, that I will able to help You out...........................................There were, So Many "Different" Thermoquad Carburetors made, over the Years, that they were Manufactured/Produced, like You wouldn't believe...!!!...............................................It seems, that, each and every Thermoquad, was Designed/Calibrated, for not only Each Engine Size, and then some, but also, there were "Differences" in the Engineering/Calibration, for "Automatic" and "Manual" (standard transmission, with the Clutch Pedal).................................................Seeing as how, You were saying, that You had a "340" with a "Manual"...???........................................I'm thinkin', that "Manual", that You indicated, might be a..."4-Speed-Manual-Transmission"...perhaps...???......................................Maybe even an..."A-833-4-Speed-Manual-Transmission"...perhaps/maybe...???....................................Even..."If"...the "Thermoquad" that You have currently Installed on Your 340, happens to be Originally Designed/Calibrated for an "Automatic Transmission", I'm pretty sure, that, we should be able to make it..."Smoke-the-Tires"...without too much difficulty, once that good ole Thermoquad Carb, gets sorted out............................................Now then, there are Numerous (aka, Many) Things, that can cause a "Rich-Running" Thermoquad alright.............................................Maybe, I'll start with...let's "Assume", that Your Thermoquad carburetor was "Rebuilt-100%-Correct"...then, as I see it, the very "First" thing, that I Noticed, in Your Comment, is Your..."Camshaft"...with that "502-Lift"...........................................While I'm at it, was Your 340's Camshaft "Lift", Measured at the Camshaft's "Lobe/s", or was it "Total Valve Lift"...??? (just wonderin', that's all)........................................When-ever a "Camshaft", that "Sounds" like it's going..."Cha-Chugg"..."Cha-Chugg"..."Cha-Chugg"...while the Engine is fully warmed up, and just "Idling", like Most, quite..."Aggressive Camshafts"...usually Do, as Opposed to a "Factory Stock" Camshafts that, shall we say..."Behaves Itself"...as in, not so much..."Cha-Chugging"...has me thinkin' the following...................................................When-ever a, shall we say..."Performance Camshaft"...is Installed in an Engine, that has..."Quite-a-bit"...or..."Lots"...of..."Overlap"...in its..."Design/Manufacture"...then, it's usually the...Additional "Overlap" (over and above that, of a Factory Stock Camshaft), that usually has a Person/Mechanic..."Adjust" the Idle "SPEED" Screw "Clockwise"...Way Too Much, in order to keep the Engine, with that "Lots of Camshaft Overlap" from..."Stalling", which is What, usually "Causes", in many cases, that..."Eye-Watering-and-Way-Too-Rich-Running-Engine...!!!...................................................Please, let me explain, what's "Goin' On".............................................Once the Engine, with that Camshaft, that has that "Large Amount of Overlap" is fully warmed up to Operating Temperature, and, when-ever You Adjust the "Idle Speed"...Higher...with the "Idle-SPEED-Screw", or "Solenoid", if so equipped, then, the "Primary Throttle Plates/Butterflies", will then be "Opened Up Too Much", which will Result in, Enough..."Air Flow"...through the "2" Primary "Venturi-ees/Throttle Bores", that, will then, start to Allow/Make the, shall we say...Primary "Low Speed Circuit" (1 Nozzle, as seen in Each Primary Venturi/Throttle Bores), in the Thermoquad, start to, and keep "Flowing", an "Air/Fuel Mixture", that is actually being..."Added"...to the Already..."Flowing"..."Air/Fuel Mixture"...from the..."Idle Circuit"...that is being Controlled with the "2-Idle Mixture Screws", in the Thermoquad, at "Idle Speed", which is what usually Causes that...Way Too Rich...and...Wasting Gasoline Scenario, that nobody really wants...!!!..............................................Thermoquad carburetors, as I see it, and maybe with the exception of something like a "Competition Thermoquad" carburetor, were Only intended, and Engineered/Calibrated, for, the Engines that were Installed in Vehicles, at the "Factory", that, for the most part..."Did Not"...have Engines, that had..."Very High Amounts of Camshaft Overlap"...thus, the reason, that, the good ole Thermoquad carburetor..."Will Not"...Operate Properly..."Until"...something is done, to, get those..."2-Primary Throttle Plates/Butterflies"..."Closed Down"...Close, to where they usually are/should be, when a Thermoquad carburetor is "Installed" on a somewhat "Factory Engine & Factory Camshaft".............................................When-ever an Engine is fully warmed up to Operating Temperature, and, is equipped with a Thermoquad carburetor, the "Only"..."Air/Fuel Mixture"...that the Engine should be "Inhaling" through the Intake Manifold, should..."Only"...be coming out of the Thermoquad's..."Idle Circuit" (that would be, the Air/Fuel Circuit, that the "2-Idle Mixture Screws Control), in order to..."Transition" (aka, make its way), "Properly", up to, and through the Thermoquad's..."Low Speed Circuit"...Properly, so the Thermoquad carburetor, will be able to, keep the "Air/Fuel Mixture", at the Proper "Air/Fuel Ratio", that the Thermoquad carburetor was Designed/Calibrated to "Feed/Administer", to the Engine in question.......................................What the "Old School Guys", used to do, to, shall we say..."Correct"...this Problem, of having the Thermoquad's..."Primary Low Speed Circuit"..."Feeding"...the..."Extra and Not Wanted"...Air/Fuel Mixture...when the Engine was fully warmed up to Operating Temperature and "Idling", was to actually..."Drill" a Small Hole, in Each of the..."2- Primary Throttle Plates/Butterflies"...somewhere "Between", the "Transition Slot" (nearest the Front of the Thermoquad carb), and the "Throttle Shaft", in order to "Provide" some "Additional"..."By-Pass"..."Air"...so that, the..."Idle-SPEED-Screw"...can be Adjusted Properly, so, the Thermoquad's..."Low Speed Circuit"..."Does Not" Feed, any Additional, and Not Wanted..."Air/Fuel Mixture"...to the Engine, while it is Only at..."Idle Speed"...!!!.......................................Some of the Performance Carburetors, that are sold these days, actually have, a, shall we say..."Idle Air By-Pass"...Feature/Adjustment in/on them, to make sure, that the "Throttle Plates/Butterflies" are in the "Correct and Needed"...Position at Idle Speed..so, the Carburetor will Work Correctly, at all Engine Speeds and Loads..................................................Could also be, that, One, or Both, of Your Thermoquad's Carburetor..."Floats", especially, if they are made out of that..."Nitrophyl" (aka, looks like black plastic) material, that may have, or are starting to Absorb Gasoline, which will cause them to start "Sinking", which will also cause a Rich Running Thermoquad Carb as well...!!!............................................I always like to actually..."See"..the "Inside" of a Thermoquad carburetor, that way, I can Verify, the Float Settings...the Sizes of the "Primary and Secondary Jets" that are Installed....the Condition, of the Accelerator Pump Seal/Cup...any Damage...just how much Debris/Crud/Yuck-ees, that might be Hiding in there...etc.)............................................So then, if Your 340's Engine, happens to have a Camshaft with "Lots-of-Overlap", then, You will have to, find a way, to get some "Additional By-Pass Air" Past the Throttle Plates/Butterflies, so the Primary "Slow Speed Circuit"..."Does Not"...Keep Feeding, all of that Extra Air/Fuel Mixture to Your Engine, while it is fully warmed up, and at "Idle Speed", or, Your Thermoquad carburetor, just won't be able to (transition) and work, like the Carter Engineers/Designers Intended them to Operate...............................................Also, some Folks, have Adjusted Their..."Ignition Timing"...in order to be able to, get the "Idle-SPEED-Screw (or Solenoid, if so equipped) "Down", close to where it should be, but, "Make Sure", that, You Fully Understand, all about..."Ignition Timing"...and its..."Effects"...on the Engine, or, there is, as I see it..."A Strong Possibility"...that..."Major Engine Damage"..."Might/Will Occur...!!!........................................Oh Yeah, if and when the Idle Speed is..."Set Correctly"...You should be able to see, once the Thermoquad is removed from the Intake Manifold, that is, and held "Upside Down"...that the "Transition Slot"...that You see, that is "Exposed/Open", just Under the Throttle Plates/Butterflies, should be about the Shape of a Little "Square" there-abouts....................................................If "Too Much" of that "Transition Slot" is Showing/Exposed" Under the Throttle Plates/Butterflies, that's tellin' me, that, by being, that much too open, has a good possibility, that the Thermoquad's..."Low Speed Circuit"...just might start..."Feeding" that "Very Unwanted and Extra" Air/Fuel Mixture at "Idle Speed", and also, Not wanted "Fumes" and Lack of Gas Mileage/Kilometer-age as well...!!!............................................Have You had a Look at Your Engine's "Spark Plugs" at all...???....................................If and when, You manage to get Your Thermoquad..."Dialed In"...and it gets close to, how I was able to make them Perform, and at times, with pretty good Fuel Economy as well, but Only when, I'm Not Doin', the...Pedal-to-the-Metal...what-sham-ah-call-it...lol...................................................So, I'll leave You with (all of...lol) this Information, and, if You decide to stay with Your Thermoquad, I'll be around here somewhere.............................................'Till next time...................................Be Safe, take care, and have a good one.
...if your Thermoquad passed the Accelerator Pump Stream-Squirting-Test, then, there is still trouble in Paradise....Change your Fuel Filter lately?....They can, and do plug-up occasionally, as well as a weak fuel pump, can cause a lean running condition....The Thermoquads choke pull-off diaphragm, as well as your vacuum advance diaphragm can deteriorate with heat and age....Before i go any further, let me know all of your Thermoquads symptoms....Like, does it start and cruise ok?....Take care
Which is mostly gone now. Also, need I mention, that you're awesome? lol
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
Here a similar set up but it s a 451 ( 400 block with 440 crank ) 4000 # car and driver.
ua-cam.com/video/pFi8cpm0a9g/v-deo.html
tetedemarc Greetings tetedemarc...I saw that "Drag Racing"..."Station Wagon"..."UA-cam Video"...of Yours, and the "Engine", sure Sounded..."Very Impressive"...alright...!!!...........................I did leave a "Comment", under that UA-cam "Video of Yours"...................Till next time...........Be Safe, take care, and have a good one.
Greetings William Ruescher....(jumping in my "Time-Machine", and heading back to 1976)....First off, I'd like to say, if your Thermoquad hasn't been re-built at all lately, and your Thermoquad has never been removed from your intake manifold, then, more then likely, some of your Thermoquads working parts may have either deteriorated or are just plain worn out....There are many culprits that may be causing your Pick-em-up-trucks poor running issues....(con't)
Hello Sulivanyk....I'm sorry, but I don't speak your Language....I only speak English....Maybe you can find someone where you live that can "Translate" your Language into English, and English, back into your Language....I'm always willing to help people, whenever possible....So, if you can ask questions in English, I will be able to help you with almost any questions that you may have....Take care my Friend, and have a nice day.
...make sure that you Manually push the Fast Idle Screw down, to the bottom, so that is off of all the fast idle Cams Steps!....If you don't, then, your primary throttle plates will be open a bit!...(Also remember to mark and record the setting that you had on the curb idle screw or solenoid, so you can re-instate the original idle speed setting later)...Once you have the primary throttle plates 100% Closed, then, stuff some clean paper towel into the primary throttle bores for safety...(con't)
...try this first...Find a small diameter piece of Fishing Line, and see if you can Probe the plugged nozzle with it, as this might dislodge, or, open up the clogged tube...You might also put a small amount of Carburetor Cleaner or some other type of solvent that is strong enough to dissolve, what I think is dried up gasoline residue (cuz, when gasoline evaporates, it usually leaves behind a brownish, dried glue like substance, and perhaps, this is your Culprit?)..Maybe do both tubes?...(con't)
...make sure that, after you put the "Clean" gasket, squirter cluster, and tighten the screw on top of the squirter cluster, that "ALL" Parts, pieces, bits, crud, and don't forget to remove "ALL" of that protective paper towel that you put in the primary throttle bores, or, Engine Damage Will be the Result!!!....Then, re-set your Idle Speed Screw, or Idle Speed Solenoid to where it was, just before you started all of this, to get your Engine idling back where it was before..Good Luck..Bye 4 now
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
...make sure that you Manually push the Fast Idle Screw down, to the bottom, so that is off of all the fast idle Cams Steps!....If you don't, then, your primary throttle plates will be open a bit!...(Also remember to mark and record the setting that you had on the curb idle screw or solenoid, so you can re-instate the original idle speed setting later)...Once you have the primary throttle plates 100% Closed, then, stuff some clean paper towel into the primary throttle bores for safety...(con't)
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)
...and, if, after you went Fishing (Thermoquad Fishing, that is), and if it's still plugged, then you'll have to remove the Accelerator Squirter Cluster...."Warning", "Caution", Destruction may be on the horizon!!!, if you don't keep those small parts from getting down into your Engine, causing total destruction (of your Engine, that is!).... If you remove the Squirter Cluster, first, back off your Idle speed screw or idle solenoid to close your primary throttle plates, and...(con't)