Rebuilding Zenith-Stromberg CD-175 Carburetors - Reassembly
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- Опубліковано 20 чер 2020
- In this video, we're putting a ZS carburetor back together after stripping it down for inspection. There were a number of variations on these carburetors, but most will be substantially similar apart from needle numbers, float height, and so forth. A quick search or a shop manual can help you with the particulars for your car, but this will give you the general knowledge needed to properly assemble your carburetor. Don't forget to subscribe to the channel to see future videos as we post them!
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Thanks for such a detailed series of videos. I’ve just rebuilt a pair of carbs and your video was a massive help. 😊
Glad it helped
Thanks for the video and detail info, been struggling with a 75 mpb and found what the issues were because of your detailed info, thanks again for a great running mgb.
So happy to hear this! Please share the channel and subscribe if you haven't already. The goal is to get more cars back on the road!
these strombergs are like black magic to me.... this is an absolutely top quality teaching video. Makes me think I might do mine by myself.
It's certainly worth a try. We all need to start somewhere, so give it a go. There isn't anything on these that can't be repaired or replaced, so the worst case scenario is just a little more cash. If you find you don't have the patience, just get in touch with me through midwestmotoring.com--I renovate these for people nowadays.
I really appreciate your detailed and instructive video. I am working on my carburetor and I don’t know what I would do without your guidance. Thank you!
Glad to be helpful!
Thanks for these great videos! I have been a Triumph guy since 1975 at the age of 17 but have never had to do anything with the carbs. Just finishing engine rebuild on a TR7 that had been in a garage for 30 years so wanted to rebuild them. Your videos have taken the fear out of it! I do have to figure out a the very weird water fed choke setup though. At first look it appears that there is not choking applied to the rear carb.
I've never been a fan of the water chokes, but if you really wanted to you could bypass them and put in a cable. I think there's a kit available somewhere...
Thank you. Very helpful video .
Glad it was helpful!
Best video I've seen on this, especially reminding me how important the float distance is. I have a TR6 and an MGB, both running poorly. Just bought 3 kits so I guess I know what I'll be doing this weekend.
Hope the weekend went well for you. Get those cars on the road!
@@midwestmotoring I watched your distributor video and OMG my MGB runs great now! First time in a decade! No need to open the carburetor.
My TR6 is awaiting 4 gaskets but fuel leak is fixed. However, my needles are immobile. Almost exact same carb as my B so I know they should move, like they do in your video. Also, no way to adjust from below, which is something you mentioned. I saw a comment about some immobile needles. My TR6 is a '76. Carbs say 175 CD-2 and look exactly like yours. But neither needle moves.
@@allenslocumb8278 in 1976 the needles should definitely be adjustable. Look for a slot machined in the top of the pistons when you look down the top of the dashpot. If there's a slot, then you have adjustable needles--they might just be stuck or the opening for the tool could be rounded off, etc. Just because there are adjustable needles though... doesn't mean they're going to want to move. You can free them up though, so don't get discouraged.
great video
Glad you enjoyed it
In the rush of things I failed to thank you for the advise on the Jaguar xke high rpm issue . You were spot on about the bypass valves and the car now runs perfect. Now I have a Gt6 that after rebuilding the carbs will not start unless choke is used and is mediocre at best. All hoses checked, fuel is reaching the float bowls. Confused about it.
Always start with the timing. If that's off, no amount of fiddling with the carbs will help. After that, if the carbs have been rebuilt and set neutrally, then remember you do need to do some tuning still since a neutral setting isn't the same as an ideal setting. It's just close enough to get the car started, and then you do the tuning afterwards. Assuming you've gotten the carbs tuned and it still won't work, now you need to start looking for something a little more hidden (such as a vacuum leak, or a failed component somewhere).
Hi a great video, and it gave me confidence to buy a rebuild kit and recondition the twin carbs on my Triumph 1850 dolomite.But when I put them on the car I could not get the car to idle and have tried everything including taken off the carbs ( no easy task ) three times and its only today I have managed to get it to tick over. The cause? the cold start adjusting screw was screwed out too far. Now I have slackened it off it will idle.So my question is what should the gap be from the adjusting screw to the cam.I think I set it at 10 thousand on the feeler gauge.
If the cold start screw is only 10thou from the choke cam, it's probably too close. I don't remember the spec, but it's in the shop manual. Probably closer to 1/8 inch if we're talking about the same thing....
Great video. A question, when you push the adjusting screw down into the piston where do you stop? I read somewhere that there is a ledge to make it stop. Is the needle flush with the top of the piston when fully turned clockwise? I noted my adjusting screw for the needle carrier locked it into place, it must have been an aftermarket screw I actually had to shorten it to make sure the needle would move up and down, before screwing the adjusting screw in with the hex driver.
Yes, that's correct. The adjustment screw won't come out the bottom--the lip on the screw is too large to fit. Just push it as far as it will go. No need to force it. For the needle, there should be a slot where the locking screw fits in. This prevents it from turning. Just make sure that slot fees the hole where the locking screw goes in on the side of the air piston. The needle will be flush somewhere in the middle of its travel. It can actually recess into the air piston, which would make the mixture richer since the needle would be thinner where it hits the jet.
You are a excellent teacher!!! my question is that vacuum line by float bowl that was pluged where does it go? mine was pluged to and cant find where it goes? Thanks I have a1972 tr6
I have the same question
Hi guys! Sorry--the wife and I just took in 3 foster children, so I have been slow at answering questions! You'll need to be more specific, but I THINK what you're asking about is the tube coming out at the base of the carburetor just under where the throttle is. If that's the case, then there are 2 types of vacuum opening you'll find. These are "ported" and "manifold" vacuum. The only difference will be which side of the throttle plate the hole is on, and (at least in a Triumph or MG) both will generally go to the distributor. Why 2 different taps for vacuum? Well, because they're on opposite sides of the throttle, one will have a high vacuum with the throttle closed (manifold vacuum) and the other will have next to no vacuum (ported). Some distributors are set up to advance or retard under specific engine loads. For example, when you let off the throttle, you'll have a very high vacuum with manifold vacuum, but somewhat lower with ported. The engineers may decide to use that difference in vacuum to change the timing depending on what the engine needs. In later TR6s, the vacuum is separated from the distributor. It actually doesn't do anything except when the engine starts running hot. The coolant running through the thermostatic vacuum valve opens a gateway when the temp goes up. That causes the distributor to advance and speeds up the RPM to raise the fan speed slightly and cool the engine. Pretty clever, huh? Early TR6s, by the way, have more than one vacuum capsule, and both operate for different reasons. Again, sorry for the late reply!
@@midwestmotoring thanks for the reply. I normally work on old chevy's. I have never heard of a distributor that needs manifold vacumm.
Nice vid. I've not done a ZS but can do an SU HD8 with my eyes closed. Looks like these are similar in principle. I like the way the needle is adjusted up down on these. The HD moves the jet body sealed with a diaphragm. Ethanol gas turns the diaphragms to rock hard, then they split and flood the engine with raw gas (and they ain't cheap)! Not sure but that may be what happened to your vac chamber diaphragm.
Careful with that background "noise". Don't want to attract the cr weenies.
They're identical in principal, yes. ZS are easier to put together in some ways since it's not necessary to center the jets like in an SU, but they have other areas that make things complicated, like the addition of a bypass valve and the temp compensator. The basic carb though is the same.
Me again! So I got the carbs reassembled, put them on the car and it fired right up!! Thank you again for all of your help! 3 additional questions - the water chokes never really turned off so I am pretty sure I do not have the heat mass/sink with the spring clocked right. In the Jag manual it says that there is an alignment mark on the heat mass/sink - do you know what this looks like? Also, I am assuming the choke components need some sort of lubrication - can you recommend what to use? Sorry for all the water choke questions, but I don't know who else to ask. Lastly, the needle adjustment screw that goes down the tube had a bad o-ring, but nothing in the rebuild kit looked correct for it. I did put on a generic one from an o-ring kit I have, but I don't think it was big enough so the oil I added is running out. Is there a place I can get this o-ring or do I just need to buy new adjusters which come with new orings? thanks again!!
Unfortunately I don't know much about the water chokes. It's one of the few bits that are outside of my wheelhouse with the exception of just cleaning them. No lubrication is generally necessary, but a dab of very light grease would be all I would use if anything. Especially with the regular choke, you don't want anything to get drawn into the holes since it'll just clog everything up... so I've never lubricated anything in the carbs. There should be an o-ring in the rebuild kit, but if not it's possible yours either was the wrong size or that it was the wrong material. You can get the right part directly from Moss and other suppliers, and it can even come with a new adjuster if necessary.
Looking thru this, I think I can dig in to the carbs on my 73 XKE. Practice on the spare carbs I purchased, then the ones on the car. Thanks for posting in detail. I have an ultrasonic cleaner. Would you recommend for the parts?
Absolutely. I use my ultrasonic cleaner for all carb rebuilds!
Thank you for this helpful video. I'm in the middle of rebuilding mine and I noticed that the bowl vent needle on one of my carburetors is free, but it does not stick out as far as the other one or as far as the one in your video. It only sticks out maybe 1/4 in where the other one is at least one half inch out. But it is free, spring loaded and it does push in when the throttle is closed. Is this normal?
I'm not sure it matters so long as it's free, but I'd try spraying some WD40 down there to see if it frees up (assuming the carb is off the car). Otherwise, if it's working, I'd leave it alone.
Do you have any advice ensuring the starterbox holes are propertly cleaned / not clogged? the holes from your video seem much more prevalent from mine when taking apart.
Actually yes. I can't recall if the video shows it, but you can disassemble the starter box partly by undoing the nut, removing the spring, etc. If you push in on one side, it'll actually separate into 2 halves--enough to at least make sure you can spray some fluid in and clean it out. You might be able to see light through the holes too. In the carb body itself, some pipe cleaners and a bit of solvent work wonders.
thx, just wondering.
wouldnt it be better to put the new o rings in back in lubricated ?
that might also give some protection to the bio fuels
(just about to revise one on a volvo b21a)
Hello! A little lubrication won't hurt anything, and might even aid assembly but probably isn't strictly necessary. As for bio fuels, most of the time this refers to the natural rubber deteriorating due to the harsh chemicals and additives in fuel. The switch to more ethanol is a major concern here, or at least that's what you'll find people complaining about in forums. However.... the seals you're installing from the new kit are probably not natural rubber, and are much more likely nitrile, viton, or some other more modern material. These materials are not going to break down in the same way, or at least won't do so as quickly. It will be time, not the fuels, that causes problems with these. You may still have issues with varnishing from infrequent use, of course, but that also won't be the seals' fault.
Will be rebuilding/Cleaning the Es carbs this Saturday, is it necessary to take the butterflies off? thank you for these great Stromberg videos.. made note of the areas to check and clean.
No, it's not necessary, but you won't be able to change the throttle shaft o-rings without removing the throttle. If that's not needed, then it's not a problem.
Thank you, then I did note where you used threadlocker blue to hold those little screws. That was why I was reluctant to take them out
what do think of weber 32/36 replacements with the P trap manifold adapters ?
Good question. I'm not an engineer, so I can't comment with authority... but my understanding is that the shape of the manifold puts a sharp turn in the path the atomized fuel needs to take. It can lead to fuel pooling in the bottom of the manifold and is therefore less efficient. The weber downdraft is a good carburetor, but what it does with accelerator pumps and idle circuits... a CD carburetor such as an SU or a Zenith-Stromberg does automatically and without needing extra work--the vacuum simply changes the size of the choke automatically. In short it's not better--just different. I doubt there's any performance advantage at all, and may be a loss.
Love the video! I am in the process of rebuilding my 74 TR6 with CD-175 carbs. I was curious what the secondary brass "jet" is next to the main jet? I had one that was damaged and cannot figure out what the part is to order a replacement. Thanks in advance for any help you can provide!
Do you mean the 2nd brass tube sticking down into the float chamber? I believe you're looking at the feed for the starter box (choke). It makes the path for the fuel for a richer mixture with the choke knob pulled out.
@@midwestmotoring yes! That’s what I’ve figured out it is because it leads up through to the choke. Any idea what the is technically called? I cannot find a replacement anywhere because it’s not listed on most diagrams.
@@Znf218 I'm not sure what it's called, but it's probably just a bit of tubing pressed into place. It's possible the depth into the float bowl is important, but I don't know for sure. Perhaps you could cut the damage off and add a bit of pipe on the bottom to keep the length the same? Otherwise maybe drill it out and press a new piece back in using tubing of the correct diameter.
@@midwestmotoring Yeah I was able to get it out and its just a small piece of brass pipe. I think that's what I will do. Thank you so much for your reply and again for the video!
@@Znf218 I'm happy to help! Sorry for the late reply. How did it work out?
Great Video Series - Can you share where you source your parts to rebuild? Did you buy a kit for each carb or individually source each item? I have a SIII E Type with 4 Zenith-Strombergs, one is leaking fuel out the plastic chamber plug on the bottom, another is leaking oil in the dashpot assuming the o-ring you showed in this video. Do you recommend a full rebuild each time? Thank you for the videos!
Great questions. I find that the general rebuild kits have a LOT of extra gaskets to fit multiple versions. They also don't tend to have things like the diaphragm for bypass valves. Best bet is to disassemble the carbs first and see what needs replacing. I source most of my parts from Joe Curto at British Superior. He actually makes a lot of the bits in house anyway, so it's going directly to the source.
As for a full rebuild each time, that's not strictly necessary. Actually (if you drive the car regularly) after the first rebuild, about the only part that will occasionally fail will be the needle valve in the float chamber. Have a couple on hand and you'll be able to make a quick repair later. It's sitting in the garage for months that makes the carb bits fail.
I'll add that you won't always want to have the car down for a week while you wait for parts. If that's the case, and if it hasn't been rebuilt in a while, I'd have all the gaskets and such on hand. That way, if you bought too many parts, you'll just have spares when you need them.
Man - I am just struggling with the throttle shaft o-rings and retainers. Is the way they are shown in the carb you disassembled correctly placed? If so, How do you get the brass retainers started and seated and make sure that the edges don't crush the "lips" on the lip side out o-ring? the retainers are actually flared further out than Rough opening of the hole it is going into (not by much so pretty sure I have the right size) so having a hell of a time getting it started.
It's a press fit so they'll stay in place. Once you get them started they go in pretty easily. As for orientation, flat side in, lip side out.
Hi Sir..when I read the manual stromberg type carb, it.mentione that the jet should be as level with a bridge to get ideal mixture not too rich (if level lower) even not too lean (if level higher)...
And so, what ideal sense to best adjust the idle port screw? What indication to show it is a fit adjustment..I try to tighten it first clock wise then return back to about 2.5 rotation anti clock wise turn..what you think sir? Thansk..
By idle port screw, do you mean the one on the side? If so, you really won't be able to adjust that without an exhaust gas analyzer. That's for extremely fine tuning, and you're better off just getting the needle close.
This is a great video series. I followed exactly and was able to overhaul my carb with ease. Just one question - how much oil to put in dash pot?
"Enough" is the answer. Technically, you should add oil until you feel resistance when pushing the damper into the piston at about the last quarter inch. If you put in too much oil, it'll just spill out and make a mess. Not enough and you'll notice when you step on the gas to accelerate the car will run lean and stumble.
@@midwestmotoring one more question. I have a ‘69 model, which i understand doesn’t have an adjustable needle. So how should i set it?
David, the 69 model might be either adjusted from underneath, or it may be in that "stupid" period where there isn't an adjustment at all. Early ZS carbs were adjusted by raising and lowering the jet rather than the needle. It's the same concept, since the important part is the relationship of the jet to the needle (so lowering the jet is effectively the same thing as raising the needle). Anyway, there would be a hex on the bottom to accomplish this.
If you have a carb in the "stupid" period, then it was an attempt to prevent owners from messing with the settings. The problem is that it was short sighted and prevented necessary adjustment as the engine wore... or if the owner wanted to do something crazy like drive into the mountains. If that's the case, you can probably retrofit your carb with an adjustable jet, but you'll need to source the parts. Otherwise, the only adjustment is by removing the float bowl and changing the height of the floats slightly, then reassembling and trying again.
@@midwestmotoring yeah, i think the stupid period. I also did a post on triumphexp and seems like the only option is the adjustable jet mod from Goodparts
I guess you could also source a set of carbs with adjustable needles. The air pistons are matched to the carb bodies, so you shouldn't technically change them... but ZS carbs use a rubber diaphragm so it's most likely not as critical a fit as with SUs. I'll bet you could replace the air pistons with a set that has adjustable needles and get away with it. Don't tell anyone else I said that though unless it works.... :)
thanks for the video ! i have a XJ12 Carb model with those Zenith Stromberg and i would like to remove the jet (the one you clean at the beginning of the video) to put a new one but it is completely stuck.. do you have any idea to proceed ?
I haven't had to remove a jet from these carburetors in the past, so unfortunately I don't really have any tips. If the jet is badly corroded or damaged somehow, that might be different though. I would suggest using a mandrel. Maybe you can machine something on a lathe (or have help doing so if you can at least get measurements) that fits around the jet and can use that to make sure it's being punched out straight. Being a little off center can make it very difficult.
@@midwestmotoring thanks for the advice !
OK - I compared the old retainers to the new ones and the old ones are smaller. I got the new ones from Moss and they had a 7MM and 9MM if my memory serves me, but they said the 7MM were no longer avail and the guy on the phone said the larger ones were the correct ones. I also notices that the inside of the housing had a lip in it from where someone drove a larger retainer it there and it "scraped" aluminum down in there and created a ledge that the o-ring couldn't get past so it wouldn't sit right. Just going to work through this and will reuse the old retainers unless I should not do this. Please advise!!
You're fine to keep working. The retainers are a pain but you'll get there. The smaller ones are for the cd150 carbs, such as on a Spitfire or gt6.
When putting the carborater back in the car, if you want to change the hoses, are the fuel hoses and the water hoses the same?
Generally no. Even though the fuel is not at high pressure, heater hoses are meant to carry coolant and won't stand up to different chemicals such as fuel for very long. Different types of rubber and different construction of the hoses can make the hose inappropriate for multiple applications. Your local auto parts store will stock different purpose hoses in a variety of sizes.
Love your music.
Thank you. I actually had to remove some of the songs from the audio to appease the boring people that write the rules. Otherwise you'd hear more of it!
Hey there - just got the throttle shaft orings (had to order separately), but the are more like a u channel molded in a ring. The ones I took out had the channel facing towards the outside of the carb/towards the ends of the throttle shaft, but they seem like they should go the other way. Can you let me know which way they should go? Thanks!
You bet! The seals should go flat side in, lip side out.
Awesome!! Thank you so much! hopefully I don't pinch them when reinstalling!
Excellent clear video thank you. Only one thing not covered. How do you replace the fixed jet ? is there a possibility it will not stay in the right position ?
The jet is pressed into place, so it's extremely unlikely to move unless you apply force from something like a hammer or drop the carburetor off your workbench onto the floor. To replace it, you have to press it back out (or use a hammer and appropriate drift), and there's a special tool to install the new one without damaging it. It's never been necessary to replace or adjust the jet in my cars with fixed jets.
@@midwestmotoring Very useful thank you. I am in the process of analyzing why does the right bank of a V12 E-type runs richer that the left bank (mostly when idling) when needles are set the same even if the right bank they are as low as possible. I check the recess of the jets and Front Right is slightly more recessed (~2,50mm) when compared to the other 3 (~2,25 mm). I wonder if 0,3 mm would be that noticeable, but i also discovered that the right bank has BIBQ needles (slightly rich at idle) and the left one has B1BH needles ! Chokes and temp compensators already checked. by-pass valves not yet checked.
The car is from 73 so the B1BQ needles should be the ones but thats the Bank running rich at idle even with needles all way down. When Cruising the mixture seems ok, nice cream colored plugs.
Oh dear, yeah you should not have different needles between the carbs. Also possible is that the floats are not set at the correct height or that the flow of the carbs are not balanced. Does the v12 have multiple distributors? Timing can also affect how rich the carbs need to be.
@@midwestmotoring once again thank you for the precious advice. It is only one distributor . In fact the suspicion goes now to float levels on the bank running richer when idling , in particular on the right front carburator. Timing is correct at 10 BDTC static ... But In cars for the US market like mine, originaly there is a vacuum retard capsule at the distributor to bring the advance to 4 degrees After TDC, arguably to reduce NoX emissions when idling by making the engine running hotter . Everybody nowaday disables the retard , by I wonder how CO lebels at 10 degrees BTDC and 4 degrees ATDC would compare .
I have replaced the valve, float and adjusted height to the 16/17 mm(5/8). No help the fuel still comes out of the vent. ( hole at the 10 o'clock) Removed and I put a little bend into the tab to try a little more pressure on the valve still no help. I just replaced the fuel pump and the forward carb is good.
How much fuel pressure do you have? If it's over about 2 psi, that's your problem. Otherwise, even new parts fail.
Where can I purchase full rebuild kits.. Something that includes everything to restore a ZS CD175 off a TR6.. I search British supplies and I get Tie rod ends, rad hoses, parts for an MG..... it's a creative mishmash of random parts. Where does one go to find the parts to restore two ZS CD175 carburetors?
Moss Motors will have the rebuild kits. The trouble you run into is that it's not a whole lot cheaper to buy the rebuild parts than it is to have someone else do the work (which I do if you need, by the way). If you do decide to take on the rebuild, it's time consuming but straight forward. I'd recommend disassembling the carbs first, take stock of what parts are needed, and then order just those parts. You won't need everything from the kits, and some of the parts you will need aren't included anyway.
@@midwestmotoring … it appears I’m heading down the 42mm Mikuni road. I have two buddies who are using them and they swear by them. I I was almost killed this summer when I entered a highway and got on the accelerator to blend into the oncoming cars and my Strombergs decided to bog out and they were useless. I was screwed and the oncoming cars had to brake drastically and I was almost run over. Not a popular guy that day. I need a car that will boot it when needed not just decide to give up a choke. That cannot happen again. Sometimes you had to leave old technology behind. Mikuni’s are not new, but their great performance is well established.
I’m also looking for a 6-2 header (1, 2, 3 & 4, 5, 6 where the front and rear carb is exhausted out the two respective exhaust pipes. I want a dual AFR gauge measuring the performance of each carburetor individually and also providing numbers to compare the balance between the carbs. No more screwing around.
Good video. Weird audio switches between left and right channel. Which sucks cause my phone has one broken speaker.
Sorry about that. Might be to do with the microphone I'm using.
@@midwestmotoring I think I figured it out. One my speakers were broken and I believe you were recording to 1 channel.
Zenith 175 cd float level. Where does one find this info? I think you mentioned 16-17 mm.
A shop manual for your vehicle will give you the correct specification. If you can't find it, you can still get results by a LOT of trial and error. Setting the floats too close to the carburetor body will result in a rich mixture (it raises the level of the fuel before shutting off flow from the fuel pump). Too far from the body will result in a lean condition. No amount of adjusting the needle up and down will ever correct the mixture if the float height is too far off. In other words, if your mixture is too rich, you can't adjust the needle to compensate, and you're 100% SURE there's nothing else wrong (such as a fuel pump that's too strong), then you can try to increase the float distance from the carburetor. It's definitely best to consult your manual though.
@@midwestmotoring i think float is only maintained fuel always ready enough when used for.combustion (during cold start idel or even high speed)
my floats are black in color but I'm thinking the adjustment is the same 16 to 17 mm?
Yes, same adjustment. The color of the floats doesn't matter, just when the valve closes
@@midwestmotoring yes it worked great, I did a total rebuild parts from moss for (2) 175 with new throttle shafts and disc, synchronizing gauge and dashboard oil was $360.00, some one before me ruined the Allen adjustment screw for these carbs but was able to adjust fuel air ratio from the bottom of the carb, I just set the needle shoulder flush with the bottom on the dash pot slide. This is all in a 1965 Morgan but it is a tr4, I am a fan of Stromberg now Lol, thanks for getting back to me.
Where can I find thinner piston diaphragms? The ones that came in my rebuild kit are too thick
I recently have started getting my carb parts from British Superior.
@@midwestmotoring thanks!
@@midwestmotoring hi sir..do younhave such online market link such ebay?
There are two holes on piston (not screw hole), where hole should located..? Directed to where air in (high pressure) or air out to throtle butterfly valve?
Two holes will let air out from membrane when piston lifted up .
In your video doesnot this showed detail..
Thanks
The holes face the engine side of the carburetor (towards the intake manifold). Vacuum from the manifold is supposed to raise the piston. The rubber diaphragm has grooves and will only fit one way also.
@@midwestmotoring thanks sir...I will apply it..
At about 3:40 you are putting in a new needle vavle and it looks like you have two gaskets (a fiber on and a metal one) - In another video, where you put in a new needle valve with carb still on car, it appears the replacement valve is put in with just a metal gasket (no fiber). My rebuild kit came with metal and fiber washers with all 3 pieces inside a small seperate bag so I know both metal and fiber are for needle valve. However, the needle valve I took out only had the metal gasket, and it also had a metal mesh filter (new valves did not have filter screeen, and these are not show in your video). Three questions : (1)The metal / mesh screen does not appear to be removable / transferable - is that just an old style no longer used? (2) Are you supposed to use both fiber and metal sealing washer? (3) In your video it appears you have put the metal washer up against carb body and the fiber washer cloesest to hex head of valve. I am thinking that maybe fiber washer should go up against carb body and metal washer should go towards hex head (exact opposite of way i think you show(?)
It's best practice to put back the gaskets that came off. The rebuild kit comes with a number of parts you won't need (they go to other versions of the carb to save on the number of different kits). I generally wouldn't put on both, as that could cause leaks.
@@midwestmotoring I first want to say thanks again for the great videos and your taking time to answer questions. I am not trying to be arguementative, and I would agree about extra gaskets in kits - however, as you pointed out, if someone has previously rebuilt my carbs there is no guarantee that they did it correctly with just the metal washer (no red fiber) for the needle valve. I have taken a close freeze frame look at both the dissambly and re-assembly videos, and while I can't be 100% sure it does look like there was both a red fiber and silver washer under the needle valve when taken apart, and when you reassembled with new valve it looks like you put in a new red fiber and silver metal? Any thoughts, and especially about if using both does the red fiber go up against the carb body or up against the hex head of the valve.
Wow, you're right. It definitely does look that way... to the point I pulled the float bowl off to check just a few minutes ago. I found only the metal gasket, but I'm not sure whether I disassembled again after the video and removed the fiber, or if maybe the metal washer was reflecting something in the video? There's always some editing done, but I honestly don't remember. In any case only one is necessary, and probably I'd go with whichever you removed from the old set.
Can you think of a reason why my Stromberg floods? The petrol does not fill the chamber but instead comes out of the middle where the jet needle is coming. I am completely out of options!
Too much fuel pressure in the float bowl. If you're using an electric fuel pump you need a regulator. Alternatively, your needle valve might have failed, the float may not be floating, or it may be set incorrectly. Also, if you have the late style of Zenith Strombergs with a tube coming out the back... that tube is supposed to be connected to the charcoal canister. If you've blocked it off, you've blocked the float bowl vent, and fuel will pour out the center like you're describing.
@@midwestmotoring Somehow the air in the float chamber compresses and forces the incoming fuel to come out of the center ....i don't think i have a blocked off vent ... but i will make a vent right away if i knew where. That exeactly seems to be the problem : no vent
The pump is mechanical and the other carb on the manifold is behaving properly.
@@egbertgroot2737 with a mechanical pump and the other carb not experiencing problems, my next guess would be a float that is leaking or a needle valve that isn't sealing. The vent is not likely to be blocked unless you've capped it on purpose.
In 1973 or 4, Triumph adopted a system where a valve would change the vent from the air cleaner to the carbon canister at idle. Sometimes people want to disable the emissions stuff (for no good reason, really) and they plug the line to the carbon canister. That blocks the vent and the carbs spew gas. If you don't have that system, you probably haven't blocked your vent.
@@midwestmotoring Thankyou for your answer. Today i will be working on that carb once again - keep you informed!
I solved the issue! Your channel was the final contribution to it: the vent was blocked with dirt!
Is there a initial setting for the idler screw?
Do you mean the idle trim screw by the temp compensator and the bypass valve? Technically yes, but you'll really need a gas analyzer to tell the difference. Just screw it in all the way and back it out about a half turn.
@@midwestmotoring
That’s the one. Thanks
I also rebuilt the temp. Compensator which bench checks fully open at 140 deg. F also the bypass valve which opens when vacuum is applied with no leaks.
What are the symptoms if either one is not working correctly when the engine is running and are there any adjustments?
I have two spare Stromberg 175 CD that need various parts but the bodies are sound, and cleaned. If you would like them, you can have them for shipping costs.
Tom Huelsenbeck
@@thomashuelsenbeck8941hi Tom, I'll take them if the air pistons and dashpots aren't missing.
As for symptoms: The temp compensator opens up to let in more air when the ambient temperature is warm. If you're starting to run rich when the engine is warm (especially while doing something like sitting in traffic) then that's a sign.
The bypass valve will open on overrun with high vacuum. So if you let off the gas and hear popping from the exhaust it's too tight. If you can't get the idle below a couple thousand no matter what you do then there's not enough pressure on the spring and it's too loose.
Sorry but the dash pots and air pistons are both missing.
Thanks for all the much needed information.
are the 175 cd2s the same ?
They're substantially similar, yes. The parts may not cross between different cars or years of carburetor. Different needles, diaphragms, etc, but that's it.
As the CD carbs developed, they basically added components. Bypass valves weren't on the first ones, or temp compensators. The choke was a little different, or they may have adjusted by moving the jet vs. The needle. The main points are identical though. If you can rebuild one, you can figure out all of them. SUs aren't that different either.
Dude - buy a 1/4” BSW/ 5/16”BSF spanner. Its the same as the battery terminal nut.
I know I know. Usually I'm not hesitant to bring home new tools. I've been shopping though....
Using your wrench wrong
I'm assuming you mean the adjustable. Sorry about that--I know there's a correct way to help keep the jaws apart at the correct distance. I should be more careful....