I have recently been gathering all the info I can find about holley type carbs it looks like they can be heavily modified for competition very impressive some models even come with linkage to allow all four barrels to open at the same time but I think for the street an edelbrock might be a better choice I think they handle down time better i.e. classic car sitting more than driven modern day gas is very clean adding marvel oil helps a lot with evaporation leaves a nice oily film I will continue to learn about all carbs I am a techno freak thank you for your tutorials
Great video! I’ve recently been working on my early 600 trying to lean out the transition circuit. My car has always fouled the plugs. When I got my AFR gauge I found that it was constantly rich at idle and cruise. Looking at the metering block it didn’t have any sort of idle feed restriction that I could see. I tapped the hole and drilled some plugs I bought. I now have a .031 IFR, now I can get my mixtures and my cruise AFR right but have introduced a flat spot just like you are talking about. I will try upping the float level and squirters like you mention. Thanks heaps
Have you seen metering blocks that don’t have any drilling’s in the vertical part of the emulsion well? I say my carb is early because it has an accelerator pump transfer tube. I have 2 like this with no drilling’s in the emulsion. I looked at a metering block that has no tube, I assume a later type, and it has 2 drilling’s about 0.25. I read somewhere that air into the emulsion at float level will allow the fuel to be drawn up sooner, bringing the main circuit on earlier. I can’t swap metering blocks because of the little tube. I will definitely try float level and squirted before I start modifying the emulsion. I just wondered your thoughts on it
Yeah I have a few like that but you actally can swap to later blocks. Tap the hole in the main body for a plug, drill it out to the right size and you should be good to go.
Great video! Cleared up a lot. I'm confused on cams though. I have a 4160 that I haven't touched the accelerator pump circuit on and before learning about it tried to fix my lean stumble with a higher power valve. Should I try a different cam first or step up the accelerator pump valve size?
The accel pump and power valve circuits are active at 2 different times. If the lean stumble is apparent instantly after hitting the throttle then its the accel pump circuit. If it lingers under heavy throttle its the PV circuit. Once you identify which one it is you can figure the rest out pretty easily. I havnt had too much luck in just switching the cams, I've had much pretty good results with installing different size squirters when trying to cure a lean stumble
Learn a lot of stuff from your vid’s great knowledge. My problem is at steady cruising on the highway afr is perfect then step on the throttle and goes way lean should I be looking at the accelerator pump or start at the power valve.
I would be looking at the power valve. If you know what vacuum reading you are at and what vacuum reading the engine starts going lean, you can select the right power valve for your combination
Great video! What tool did you use to get the accelerator pump off? I have a 4150 that I’m trying to rebuild, and I’ve never seen anything like it before!
Good channel a lot of information. Can you do a video on the idle circuit on holleys? I have a 350 2b holley idling too rich, the mix screws aren't enough to lean it out non adj air bleeds any tips much appreciated.
ua-cam.com/video/cIUhlHltPpM/v-deo.html already done. Chances are you'll need to drill into the throttle blades to let enough air in at idle. Someone did a videonon drilling them out. Ideally youll want to go 4bbl so you have 4 corner adjustment but if you need to run a 2bbl youll probably need to drill it out
@@NightWrencher its either drilling the blades or getting an adjustable metering block with adj bleeds. I heard people using thin wire to restrict the idle fuel circuit to lean the mix out, just thought maybe someone had a different idea all good thanks for replying
That's true, but if your transition is already set up well, you don't want to mess with the IFR because you'll change the setting in the transition. If the issue is related only to the idle circuit, you need to focus on those two things. Air bleeds and IFR will affect the whole curve so understand what you are planning on doing before you make permanent changes.
@NightWrencher Thanks for responding, I am trying to tune my Quick fuel double pumper 750. It appears that my secondaries are not kicking in soon enough after the primary, which is causing hesitation or stumbling on acceleration. How can I tune my carb to fix this?
I've already increased the jets from 31 to 35. I am now considering changing the pump cam, but not sure to what size as I am currently using the pink cam. Is there a science behind selecting or simply trial and error?
@@killtraccskill_onthe_beat1824 can you explain what you mean by the secondaries are not coming in soon enough? On a double pumper, the primaries and secondaries are tied together using progressive linkage so the more you accelerate on the primaries, the more the secondary butterflies will open so please describe your issue as best as you can so I can help you identify the correct circuit that is having an issue.
@NightWrencher I'm not a mechanic at all, but I'll try to explain better. It appears that when accelerating the primary shot starts and finishes a split second before the secondary begins. It's during the split second where the hesitation is happening. When reving at higher RPMs, there's no hesitation at all. Sorry if I'm not clear with my expectations
Dude the part of the video I needed most was what was slightly off camera. Ughhh gotta find another video to show what you were trying to show. Good content otherwise. I am trying to diagnose an issue and I think it's how my accelerator pump is being interacted with.
@@NightWrencher I appreciate that. I am a complete novice so I'm sorry if any of my questions or explanations are dumb. I'm having an issue where I idle fine, but when I rev the engine, it bogs midway through and then if I rev harder it sorts itself out. This causes me to stall at intersections and red lights unless I accelerate very very slowly. I have a feeling something is wrong with my accelerator pump or the connections to it.
@@NightWrencher it's a Ford 289 mated to a Holley 4160. I don't know that I can answer your timing question, but my FIL helped me adjust the timing with a timing light and I think he said it was off by 8 degrees initially. This problem also just came up within the past month.
Thats actually not totally correct and heres why. If you take a 65 jet and drill it out to a size 70 jet, it will not flow like a 70 jet. We can agree on that. But, if you keep track of where you start and you know exactly what you are drilling to, reguardless of whether or not a holley jet flows "better", you can dial in your air fuel ratio no problem. Thats what the old school racers used to do. Now, you cant flip flop between holley jets and drilled jets. Pick one route, and stick to it or you'll make a mess.
I have recently been gathering all the info I can find about holley type carbs it looks like they can be heavily modified for competition very impressive some models even come with linkage to allow all four barrels to open at the same time but I think for the street an edelbrock might be a better choice I think they handle down time better i.e. classic car sitting more than driven modern day gas is very clean adding marvel oil helps a lot with evaporation leaves a nice oily film I will continue to learn about all carbs I am a techno freak thank you for your tutorials
For the street, edelbrocks are hard to beat. For any type of competition use, Holley all day long
Thank you, that was really helpful and clear. Exactly what I was looking for. I bought the white cams and .37’s to cover a pump shot lean spike.
Nice 👌 holleys are complex but they become super easy to work on when you know what to look for
Awesome video sir. Congratulations on a continuing progression of the channel.
Very much appreciated! Thank you!
Great job explaining.
Thank you sir! I really appreciate it!
Great video! I’ve recently been working on my early 600 trying to lean out the transition circuit. My car has always fouled the plugs. When I got my AFR gauge I found that it was constantly rich at idle and cruise. Looking at the metering block it didn’t have any sort of idle feed restriction that I could see. I tapped the hole and drilled some plugs I bought. I now have a .031 IFR, now I can get my mixtures and my cruise AFR right but have introduced a flat spot just like you are talking about. I will try upping the float level and squirters like you mention.
Thanks heaps
I hope it all works out!
Have you seen metering blocks that don’t have any drilling’s in the vertical part of the emulsion well? I say my carb is early because it has an accelerator pump transfer tube. I have 2 like this with no drilling’s in the emulsion. I looked at a metering block that has no tube, I assume a later type, and it has 2 drilling’s about 0.25. I read somewhere that air into the emulsion at float level will allow the fuel to be drawn up sooner, bringing the main circuit on earlier. I can’t swap metering blocks because of the little tube. I will definitely try float level and squirted before I start modifying the emulsion. I just wondered your thoughts on it
Yeah I have a few like that but you actally can swap to later blocks. Tap the hole in the main body for a plug, drill it out to the right size and you should be good to go.
Great video! Cleared up a lot. I'm confused on cams though. I have a 4160 that I haven't touched the accelerator pump circuit on and before learning about it tried to fix my lean stumble with a higher power valve. Should I try a different cam first or step up the accelerator pump valve size?
The accel pump and power valve circuits are active at 2 different times. If the lean stumble is apparent instantly after hitting the throttle then its the accel pump circuit. If it lingers under heavy throttle its the PV circuit. Once you identify which one it is you can figure the rest out pretty easily. I havnt had too much luck in just switching the cams, I've had much pretty good results with installing different size squirters when trying to cure a lean stumble
Learn a lot of stuff from your vid’s great knowledge. My problem is at steady cruising on the highway afr is perfect then step on the throttle and goes way lean should I be looking at the accelerator pump or start at the power valve.
I would be looking at the power valve. If you know what vacuum reading you are at and what vacuum reading the engine starts going lean, you can select the right power valve for your combination
Great video!
Thank you sir!
Great video! What tool did you use to get the accelerator pump off? I have a 4150 that I’m trying to rebuild, and I’ve never seen anything like it before!
I have a video on a 50cc accel pump, it might have the info you are looking for 👍
Good channel a lot of information. Can you do a video on the idle circuit on holleys?
I have a 350 2b holley idling too rich, the mix screws aren't enough to lean it out non adj air bleeds any tips much appreciated.
ua-cam.com/video/cIUhlHltPpM/v-deo.html already done. Chances are you'll need to drill into the throttle blades to let enough air in at idle. Someone did a videonon drilling them out. Ideally youll want to go 4bbl so you have 4 corner adjustment but if you need to run a 2bbl youll probably need to drill it out
@@NightWrencher its either drilling the blades or getting an adjustable metering block with adj bleeds. I heard people using thin wire to restrict the idle fuel circuit to lean the mix out, just thought maybe someone had a different idea all good thanks for replying
That's true, but if your transition is already set up well, you don't want to mess with the IFR because you'll change the setting in the transition. If the issue is related only to the idle circuit, you need to focus on those two things. Air bleeds and IFR will affect the whole curve so understand what you are planning on doing before you make permanent changes.
Mine was totally opposite. Previous owner mistook brown as being orange. Needed to down size
My charger is the same way. Doesnt need much fuel to get it going but my truck wants a bunch of fuel
Min will not accelerate when I mash the accelerator runs and idles but won't rev
I found if my floats where high they would drip out the boosters.
Are you still answering questions on this?
Yes sir, whats going on?
@NightWrencher Thanks for responding, I am trying to tune my Quick fuel double pumper 750. It appears that my secondaries are not kicking in soon enough after the primary, which is causing hesitation or stumbling on acceleration. How can I tune my carb to fix this?
I've already increased the jets from 31 to 35. I am now considering changing the pump cam, but not sure to what size as I am currently using the pink cam. Is there a science behind selecting or simply trial and error?
@@killtraccskill_onthe_beat1824 can you explain what you mean by the secondaries are not coming in soon enough? On a double pumper, the primaries and secondaries are tied together using progressive linkage so the more you accelerate on the primaries, the more the secondary butterflies will open so please describe your issue as best as you can so I can help you identify the correct circuit that is having an issue.
@NightWrencher I'm not a mechanic at all, but I'll try to explain better. It appears that when accelerating the primary shot starts and finishes a split second before the secondary begins. It's during the split second where the hesitation is happening.
When reving at higher RPMs, there's no hesitation at all.
Sorry if I'm not clear with my expectations
Dude the part of the video I needed most was what was slightly off camera. Ughhh gotta find another video to show what you were trying to show. Good content otherwise. I am trying to diagnose an issue and I think it's how my accelerator pump is being interacted with.
Comment section is always open if you need me to answer a question
@@NightWrencher I appreciate that. I am a complete novice so I'm sorry if any of my questions or explanations are dumb. I'm having an issue where I idle fine, but when I rev the engine, it bogs midway through and then if I rev harder it sorts itself out. This causes me to stall at intersections and red lights unless I accelerate very very slowly. I have a feeling something is wrong with my accelerator pump or the connections to it.
Let me ask you this first before we dive into fueling(I don't think its the accelerator pump). What engine and What is your initial and total timing?
@@NightWrencher it's a Ford 289 mated to a Holley 4160. I don't know that I can answer your timing question, but my FIL helped me adjust the timing with a timing light and I think he said it was off by 8 degrees initially. This problem also just came up within the past month.
@@NightWrencher are you on Instagram? Anywhere I can direct message with you?
I enjoy your videos, however you should not drill a Holley jet because Holley jets are flowed unlike other jets
Thats actually not totally correct and heres why. If you take a 65 jet and drill it out to a size 70 jet, it will not flow like a 70 jet. We can agree on that. But, if you keep track of where you start and you know exactly what you are drilling to, reguardless of whether or not a holley jet flows "better", you can dial in your air fuel ratio no problem. Thats what the old school racers used to do. Now, you cant flip flop between holley jets and drilled jets. Pick one route, and stick to it or you'll make a mess.
@@NightWrencher lol I am one to make a mess.
🤣
Edelbroch are for those who cannot tune.