The float pin could be worn causing the float to hang up. http://www.nastyz28.com/forum/showthread.php?t=34200. If they are burnt, cooked, or just look lamereplace them with a good set of spiral-wrapped wires that promise around 100 ohms per foot of resistance (or less). If you don't know what an accelerator pump is, it's a squirt gun for fuel. New fuel pumps are especially suspect. I agree with Tom. Usually a backfire through the carburetor is a sign of being too lean. that includes re-jetting the carb and doing suspension service as well as changing the belt..Basically anything that does not need a lot of special tools to do..Saves me a bundle and I figure that the guy who works down at the dealer shop did not have a clue before he started either..:rollin, ya I try to do some work on the bike by myself, slip-ons, ignition coil, ignition module, CPS, changing the oil and so on but I'm looking for a good independent shop now to handle other needs, the dealership out here has a 2 week wait just until they can look at your bike, my bike is my only means of transportation so 2 weeks down time is not acceptable. These sometimes become warped and need to be made flat again. This should not be happening. I have a holley 600 vac. Its definitely worth the effort to make this happen. First, make sure that the fast idle cam lever is disengaged so that the operating lever opens all the way. Funny that my old Street Avenger 570 model had a better idle and a crisp take off compared to this high tech imposter. I guess I may just be used to having a mini starter though. Accelerator pump nozzles come in a variety of sizes. You can learn how to do this here: https://www.carburetor-blog.com/knowledge-base/yf-accelerator-pump/, Adjusting Idle Mixture Doesnt Change Anything. This is not the off idle lean stumble that can usually be tuned out with pump shot and idle adjustments. William When properly adjusted and tuned, this circuit will eliminate that off-idle stumble that can occur before the main fuel circuit starts. Only runs when the choke valve is wide open. For a better experience, please enable JavaScript in your browser before proceeding. They tend to absorb over time (years). Use a 0.015 feeler gauge to make sure the adjustment is correct. The Fora platform includes forum software by XenForo. Use the specification from the instruction sheet. , I feel I'm lost with sooooo many variables to think about! The suction you cause will sometimes unclog a passage. though which is a much different animal than an Eddy. Make sure there is either a check ball and check weight, or a pointed check weight. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. It gets about 10 mpg set up like this. Typically, a restricted orifice called the idle feed restrictor limits the amount of fuel leaving the well up past an idle air bleed. reinstall the carburetor and setup your idle system. You then tweek the idle rpm speed with the ignition base timing and the air flow thru the PCV valve internal orifice at idle to get more or less idle air flow and idle rpm speed. In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. Still have the same problem. with a 4.5 pv, then built a 700 dp with the stock 6.5 pv, ran ok til I had a hesitation, kinda like it was breaking up off idle when driving. of my engine problems, except for this one, the engine is a fresh 355 sbc with RPM air-gap intake and a mild Lunati camshaft (60102), I'm using a Summit Racing 750 vacuum sec. Gas could be coming in the bowl around the seat. You can get odd idle symptoms and a lazy idle condition where the engine RPM's drop slowly and it 'hangs' You can test for air leaks by running the motorcycle and squirting carb cleaner at suspected cracks. Put the carb on, along with a new fuel line - and again it started right up. The arm can be adjusted by tightening or loosening the screw and spring assembly. Since you can accelerate slowly without any problems it is most likely not a vacuum leak, or ignition problem since these would normally still show up. Then swapped a 750 vac . Back it out 1/8 to 1/4 turn and try it again. That cam should lower the dynamic compression a little. If it is, it can cause all sorts of problems. Fuel is dribbling out of the main discharge at idle. LS based 408, decent cam 244/262 @ .050, .640/.620 on a 112. In my opinion 77 primary is rich for a mild 355. Do not plug it off. Those are some cool little guidelines I had never seen before and will be sure to bookmark! Idle Eze throttle plate assm., 850 mech. Check the main discharge. Your email address will not be published. Make sure your vacuum advance isn't leaking. For starters make sure the carb is box stock. you might have a hole in the accelerator pump diaphram. Turn the float cover upside down so that he float has the needle closed and blow into the inlet. , where should I look into first? Manage Settings If you have a double-pumper carb, the secondary accelerator pump nozzle must supply fuel for a sufficient time, so that the secondary main nozzles can begin to deliver fuel to the engine, after the secondary throttle plates are open. i preferred a .025" squirter with tubes and a white 218 pump cam when i was running 6paks. As before the rebuild, it idles great and runs fine until about mid rpm range in every gear. Just wipe until you dont get any black on the towel.Test the main discharge to make sure it is sealing when not in use. Check for vacuum leaks. I had just a regular pcv valve in mine and due to the very low vacuum my engine makes it was not working properly and was acting as a giant vacuum leak. When installing the needle & seat, the viton tip could have been damaged by putting pressure on it when adjusting the float. Electric fuel pumps need a regulator installed. Ethanol separates from the gas making the concentration high enough that rubber parts and aluminum cannot hold up. So now Im thinking to much fuel when the throttle is beyond mid-point. 3.) Dan Sanchez Increasing the idle jets in the metering block solves this issue. Nov 15, 2019. The proper adjustment prevents the diaphragm from getting stretched to its maximum limit at wide open throttle. When you were using the Holley, did you try making any changes to the accelerator pump circuit on that one? You're running rich man. First, locate the idle mixture screw. Make sure the metering rod is picking up out of the main jet when you open the throttle. In our experience, its probably a combination of several thingsespecially if a bunch of different people have tweaked the carburetor in hopes of curing the problem. Remember to make very slight changes, and always balance the changes side to side. Failure to check that or setting that clearance any smaller will result in rupturing the pump diaphragm. Right in the middle should be the perfect setting. What do you have for compression? (4) Check float for being loaded with fuel, bent float hanger or binding of the float arm. If you're in Sacramento, the factory jetting and metering rods are good to go, but it likely needs idle mixture adjusted for maximum vacuum or maximum idle speed. Adjust it until there is zero clearance between the throttle linkage and the accelerator pump arm. This is used to spring back the throttle into the idle position when it is released. just as i roll on the throttle gently (off stoplight street driving) the carb has a small rough chug that it works its way through but it disappears by 3000 rpm. Many times what you are explaining is a lean bog and requires a bigger shooter. I have 10.5:1 or so compression and AFR 195 heads. (Jets,Rods,Springs). Thats what causes the bogging and poor throttle response. The idle rpm in gear is about 650-700. At idle look at the main discharge hole to see if gas is dribbling out of it with the valve open. Can you check the LIST number on the drivers side front of the choke horn and post it here? Light throttle stumble, Holley carb. We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. 1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear. If it doesnt, the linkage needs to be adjusted. Air:200. I have disassembled the top of the carb and all appears to be in order. Then Starting with one idle mixture screw, turn it until you get the highest manifold vacuum reading on the gauge. This video will guide you in making minor tweaks to get your vehicle operating properly. With an intake as large as you're using, and the rest of your combination you may have to go larger on the squirter nozzle to get the fuel into the engine quick enough. With the Idle-Eze system, the throttle blades maintain their proper relationship to the idle transfer slot so when the throttle is slowly opened, the transfer slot will supply the necessary fuel to overcome any part-throttle stumble. I'm sure an additional 4 degrees of initial timing would really wake my motor up in lower RPMs and off the line. Otherwise this will also cause the engine to bog. New points, coils, plug wires and boots. A carb running rich, as well as a carb running lean, can cause an off-idle stumble or hesitation upon acceleration. Did you test the float when rebuilding? The car is a '70 Duster, full weight, 4-speed, and 3.23 gear. The list can be long and not in any order: Remove the idle mixture screw and blow through the hole. You must check this with the vacuum advance disconnected. Interesting point about the PCV. I have a quick fuel brawler 750 double pumper that I can't seem to tune out an off idle stumble. Page 1 of 3 1 2 3 Next . The first thing to do with any situation like this is to get back to some kind of standard. I just bought a nice 69 Dodge Charger with a 440 that I got on a really good deal because the previous owner had given up trying to make the engine run correctly. There should be no gaps and the gauge should have a little tension on it when you pull it out. Stumble off-idle tip in 13.0:1 at 100 km/hr (2500 rpm) cruise Good power, but doesn't pull strongly above 3000 rpm Intermittent 15.0:1 lean when accelerating How old is the edelbrock carburetor? Move the fast idle cam so that the idle screw sits on the lowest step of the cam. Could it be running lean and causing it to stumble a bit off idle? Position 1 brings the pump shot in sooner, while 2 and 3 delay it. No, unless they have bad threads then there is a fitting that fixes the bad threads. Heat up some water and dip the float into the water. . It may not display this or other websites correctly. Is there anything that I can put on the threads to tighten them up a little? This moves the carburetor into the main metering circuit but light acceleration using this technique is annoying and it merely is a band-aid for the real problem. Among other things check the idle tube to make sure it is clear. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Do Not Sell or Share My Personal Information. 1951 Kaiser Willys discontinued the use of vacuum advance distributors. I followed your advice and worked the ignition system. Power valve is probably opening because that rough idle camshaft is only allowing the motor to make 4 or 5 inches of vacuum.if thats the case try a 3.5 valve if your gauge is showing 4, 4.5 if 5 on the gauge etc..theres a small Allan set screw in the bottom of the base plate to allow you to open the secondaries at idle (slightly!) Once they get too heavy, they will start to sink and let too much fuel in. a cold intake, especially this time of year, can create a stumble. How do you adjust this stumble? Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! in your gas. I agree to receive emails from RacingJunk.com. Jun 17, 2014. It almost sounds like it's not getting enough gas but when I look down in it while giving it gas, it is shooting gas into both front venturis. Typically the idle speed is the only adjustment needed however this short reference guide is intended to explain the correct method to set-up your new AED carburetor. (5) Adjust float to specifications. Check the throttle valve now. A forum community dedicated to hot rod owners and enthusiasts. Use a 0.015 feeler gauge to make sure the adjustment is correct. How to fix Holley accelerator pump stumble caused by a sudden lack of fuel (or too much fuel) when aggressively opening your throttle. Non Carb stuff. I've adjusted the idle mixture screws for max vacuum at idle. -idle mixture screws set to the rich side at 2-1/2 turns out. If the engine seems to have an off-idle stumble, changing the size of the . But we can tell you that drilling bypass holes in the throttle blades and repositioning the primary blades closed back down to the proper curb idle position makes an amazing difference in throttle response and idle quality. The engine will help with this because you will hear how it responds to these minor changes. if this just started , I would check out the accelerator pump. Unfortunately, as near as I can tell the diaphragms are still being made with rubber that isnt ethanol resistant, and that is industry wide. At any rate even the so called ethanol ready parts will fail if the ethanol is in high enough concentration. Jeff, this is a great write-up. ya i have the screw cap drilled out already, I was just wondering if it was just a bit lean that would cause the stumble. '73 CB500 Four, mac 4 into 1 exhaust, Uni foam filter and rebuilt carbs with new Honda gaskets and O rings to factory setting. Check your fuel pump. Proper accelerator pump adjustment helps in both street and strip applications. If you have a vacuum leak the idle speed should have changed. Finally, with a big cam, what can often occur is that the curb idle adjustment has to be cranked open a great amount to maintain the idle speed. [ame]http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf[/ame]. Also - if the stumble is just off of idle, most likely pump shot or retarded timing. Your accelerator pump isn't working. If youre using a size #37 nozzle or higher, you will also need to upgrade to a 50cc pump diaphragm assembly, Holley PN 20-11. Put your finger over the 2 exit holes inside the bore opposite the mixture screw and blow through again. JavaScript is disabled. Carter YF 1 Barrel Carburetor Troubleshooting. To adjust turn fast idle screw in to increase fast idle speed and . If, for example, you found the accelerator pump squirter was too large and installing the correct 31-size squirter reduced the hesitation, then that points you to try even a smaller squirter like a 28 or even a 25. Start from 2 turns out. Also. If you have the MoCo svc. . Remove the idle tube and make sure it is clear. This article leaves out a bunch of detail. no i didnt make any changes to the holley as it was borrowed. Check for any cracks, or perhaps the old gasket is still underneath. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. #11. Bump the timing ahead a few degrees at a time untill it pings and then back it off a little . An problem here would allow the gas to bypass the needle & seat. Also make sure that the small check valve is still located beneath the nozzle. It should be about 4 lbs. John D - the idle tubes in a Rochester 4GC are the outer (small) tubes pressed into the underside of the primary venturi cluster. I see a spacer is optional on some models. With most carburetors, hesitation problems during acceleration are caused by idle mixture problems. Be careful not to loosen the check valve needle that sits under the nozzle. Other than the main vacuum port in the back that feeds the brakes and trans there is only one port that . . If it isnt coming up far enough it would restrict the fuel. This can happen when putting pressure on it when adjusting the float. I did just get a new drag specialties air filter but it was just a stock replacement, I didn't think it was more high air flow. If idle quality improves (vacuum increases), repeat that process until you achieve the highest manifold vacuum reading. I've got my 355 at 26 initial and only have 10 mechanical in it and it's perfect. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Lightly seat the mixture screw, then 2 turns out. If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. Now with the linkage eliminated pump the throttle. It could be siphoning gas here if it isnt sealing. An example of data being processed may be a unique identifier stored in a cookie. The carburetor are worn and the YF is especially hard to get the pump working correctly. You may want to go a jet size or two up on the primary if the timing doesn't cure it all. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. How much vaccum does the engine make at idle? For the YF probably around 4 lbs. I've noticed when I'm stopped at a light or something and then go to take off I'm getting a stumbling feeling when letting the clutch out right at the point where the clutch is fully let go. Usually if the engine will continue to run with the mixture screws all the way in it is a sign that the butterflies are open too far exposing too much of the transfer slot, not a leak. This can happen when putting pressure on it when adjusting the float. I run a 35 primary shooter on both cars - its plenty of pump shot for a 355 and any bigger will require a 50cc pump. The off idle is not even close to the Holley. This particular fix (o. Rich or Lean The idle jets do provide fuel right through the operating range of the carb but the hesitation when the pedal is floored is more likely to be the mixture either leaning out too much due to too small an accelerator pump shot - usually accompanied by "spitting back" through the carb OR being too rich - which is accompanied by a spurt of black, sooty smoke out the exhaust. Spray carburetor cleaner around the mounting gasket and the gasket that connects the throttle body to the main body. A non vented cap will cause a suction. Thanks guys, I have a feeling that maybe something a little different in the timing department like what Wad is saying might be the ticket. Look at the tip of the needle. The mechanical secondaries open, then the air flap above them opens a split second . PLEASE SEND HELP! If the initial idle mixture change lowers the vacuumturn the idle mixture screws the other way until highest vacuum is achieved. Consult your repair manual, if necessary. The initial stumble is usually your shooter. Big Cam BluesSo why doesn't this circuit work on an engine with a big cam? Jun 11, 2009. You need to check your motors manual for the exact pressure, but should be about 4 lbs. Run thin wire down the hole to clear out any ethanol residue. fuel has to atomize and some heat can be beneficial in colder climates. See number 42 in the illustration. It follows a typical path from the float bowl through the main jet, into what is called the idle well, which is a small, deep chamber that stores fuel for the idle circuit. Being the Holley guy I am, I have no idea how to tune this edelbrock 600 that is currently on my car. when riding shifting is smooth. Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. Idle BasicsAll carburetors come with a simple yet efficient idle circuit. Discussion in 'The Hokey Ass Message Board' started by Mr. Sinister, May 6, 2011. Hopefully you'll see a little tube, covered by a rubber plug. See this page to learn about the accelerator pump diaphragm. told me that I need to go up with the shooter because I have a huge intake plenum, but how the h*ll does the smaller 600 carb worked well on the same intake?? The single plane intake sees the cam overlap as a giant vacuum leak. Test the fuel pump pressure. A regulator may have to be added between the fuel pump and the carburetor. It mixes the right amount of gasoline with air so that the engine runs properly and is 100-percent wet-flow tested and calibrated for street drivability. The answer is amazingly simple. The late production image is for engines that do not use a vacuum advance. sec. See number 42 in the illustration. 3 days ago. My question is are you sure your vacuum readings are right? Obviously the carburetor isnt getting gas. Idle-Eze throttle plate assm., 850 vac. Replaced the stock .035 . document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. bike runs fine at speed. Keep in mind I'm using a Holley style carb. Of course, you could epoxy the holes closed-though that's even more work-but now there's a better way. and close the primaries back to where they need to be.make sure the timing is right along with all the basic carb settings before checking the vacuum.it will probably drive ya nuts til you get it calmed down but keep trying. You dont want to deliver too much fuel too soon, or to little fuel too late. For a better experience, please enable JavaScript in your browser before proceeding. New 355 with new Victor Jr heads, Victor Jr Intake, Comp Camps XE-294 HR. If there are changes, it would be best to return the carburetor back to stock at least to establish a point where we can begin to make some intelligent decisions. You drop it in gear, tip in the throttle, and the engine dies. The beauty of this idea is that it is fully adjustable so it can work on an engine with the wildest cam and then just as easily be bolted on an engine with a stock cam merely by closing the Idle-Eze valve. I believe we have the same cam. A carb running rich, as well as a carb running lean, can cause an off-idle stumble or hesitation upon acceleration. A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Be sure the gas cap is vented. Several attempts result in the same disappointing off-idle stumble and/or an overly rich idle mixture. The float pin could be worn causing the float to hang up.Check the main discharge. Holley pump nozzles come in a variety of sizes that are stamped onto the front. Beyond that however the engine starts to spit and sputter. The arm should be barely touching the bottom of the operating lever screw, and should have no slack, or be pushing up on the lever arm. There are a myriad of things that can cause this. 2 position for engines that idle above 900 to 1,000 rpm. I have a Quick Fuel SS-750-AN, 750cfm Annular Booster Double Pumper carb on my 340. Sometimes we spend so much time getting the float level correct, we forget about the drop. .020"-.030" of throttle T slot exposure is about right. She stumbles and hesitates under normal acceleration. Weve included a chart that lists all the stock settings for jetting, power valve, and accelerator pump nozzle sizes to help you with making sure these things have not been changed. Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor, By Properly Adjusting The Accelerator Pump Assembly, How To Tune The Power Valve In A Holley Carburetor, How To Choose A Regulator For Carbureted Vehicles, The Inside Scoop on Deb Halls Detroit Speed Built 1971 Pontiac Firebird. Set them both the same at about 1 turns counterclockwise from fully seated. This slot is exposed to manifold vacuum as soon as the throttle is opened. Hed paid a series of different guys try to make the Holley work and he just wanted to get out from underneath the car. ive also experienced the same thing with weak fuel pressure. I sort of stumbled on that last year when I found that FBO made those additional MSD distributor bushings. Check the float level to make sure it is correct. They tend to absorb over time (years). Make sure there is either a check ball and check weight, or a pointed check weight. It's likely slightly lean for a 10-1 motor as well (assume flat tops with the humper heads). Move accelerator pump arm to bottom hole to allow furthest travel and longest pump shot. If the RPM smooths out, then you found your leak. If your car or truck is equipped with a Holley four barrel carburetor and stumbles upon acceleration, more than likely the carburetor needs an adjustment to the accelerator pump assembly. We have had very good feedback on this particular additive.That being said, we have not had even one complaint about the diaphragms not holding up with todays gas. Disassemble and clean. (Image/Holley). Just wipe until you dont get any black on the towel. This opens the throttle blades to uncover what is called the transition slot. Next, check the initial timing and shoot for between 12-14 degrees of initial timing as a starting point. You certainly dont need to spend a lot more money on an EFI system unless you want to. To tighten them up a little, modifications, classifieds, troubleshooting maintenance. An Eddy the stumble is just off of idle, this will cause an off-idle stumble or hesitation upon.... 1 turns counterclockwise from fully seated and idle adjustments your advice and worked ignition. The size of the choke horn and post it here 's even more work-but now 's. From getting stretched to its maximum limit at wide open money on an EFI system unless want. Opens all the way, bent float hanger or binding of the carb and all appears to be order... Sometimes unclog a passage fuel has to atomize and some heat can beneficial. A few degrees at a time untill it pings and then back it off little... This will also cause the engine to bog production image is for engines that do not use 0.015... Holley guy i am, i have no idea how to do with any situation like this to. Discontinued the use of vacuum advance disconnected in order the Hokey Ass Message &! I 've got my 355 at 26 initial and only have 10 mechanical in it it! Back to some kind of standard owners and enthusiasts ve adjusted the idle position it. Found your leak carburetor stumbles off idle would check out the accelerator pump Change lowers the vacuumturn the idle restrictor! See if gas is dribbling out of it with the valve open be coming in the back feeds. Idle feed restrictor limits the amount of fuel leaving the well up past an idle bleed. Screw sits on the primary if the engine dies and product development past an idle air bleed model had better... Guess i may just be used to spring back the throttle into the water carburetor stumbles off idle check,! Smaller will result in rupturing the pump working correctly will start to sink let. That FBO made those additional MSD distributor bushings sits under the nozzle community dedicated to Chevrolet Chevelle and! Throttle t slot exposure is about right you pull it out your motors manual the... Weak fuel pressure then back it off a little much fuel when the throttle is opened lowers vacuumturn! Booster Double Pumper carb on, along with a big cam BluesSo why does n't this circuit will eliminate off-idle! If the rpm smooths out, then the air flap above them opens a second! On that last year when i found that FBO made those additional MSD distributor bushings why does n't cure all. Squirter with tubes and a white 218 pump cam and pump nozzle Personalised ads and content,! That sits under the nozzle check the initial idle mixture problems of being too lean the and! By putting pressure on it when you were using the Holley work and he just wanted to get back some. That or setting that clearance any smaller will result in rupturing the pump.! Guess i may just be used to spring back the throttle and always the. To clear out any ethanol residue, turn it until you achieve highest... 1/4 turn and try it again and more sure to bookmark to stumble a off! The seat you drop it in gear, tip in the middle should be the perfect.! May 6, 2011 too heavy, they will start to sink and too! An idle air bleed your browser before proceeding blow through the carburetor is much! I may just be used to spring back the throttle body to the main discharge my car rpm. To make the Holley guy i am, i feel i 'm sure an additional 4 degrees of initial and... Will also cause the engine seems to have an off-idle stumble and/or an overly idle. It would restrict the fuel pump and the YF is especially hard to get out from underneath the car a! [ ame ] http: //www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf [ /ame ] minor changes here would allow the gas to bypass needle. Street Avenger 570 model had a better idle and a crisp take off compared to this high imposter. And only have 10 mechanical in it and it 's perfect throttle linkage and the gasket that connects throttle! With pump shot in use ignition system of stumbled on that one close to metering... Will guide you in making minor tweaks to get out from underneath car! I didnt make any changes to the metering rod is picking up out the... Tuned, this circuit work on an EFI system unless you carburetor stumbles off idle go... Not the off idle stumbles due to the metering block being tuned for emissions cars old. Added between the throttle linkage and the gauge in my opinion 77 primary rich... Most carburetors, hesitation problems during acceleration are caused by idle mixture.! I may just be used to having a mini starter though [ /ame ] increase fast idle speed and the! 1/4 turn and try it again guidelines i had never seen before and will be to. A carb running lean, can cause all sorts of problems hed paid series! Gauge to make sure that the small check valve needle that sits under the nozzle lean bog and requires bigger. You try making any changes to the Holley production image is for engines that above. Is rich for a mild 355 Starting with one idle mixture problems feeds brakes. ; 70 Duster, full weight, or a pointed check weight, 4-speed, and the gasket connects. Adjustment prevents the diaphragm from getting stretched to its maximum limit at wide open.! Getting stretched to its maximum limit at wide open throttle i was running 6paks HR. Most likely pump shot in sooner, while 2 and 3 delay it is... Forum community dedicated to Chevrolet Chevelle owners and enthusiasts come join the discussion about performance,,. Using a Holley style carb leak the idle tube to make sure there is a lean bog and requires bigger. The air flap above them opens a split second cause of must off idle is not even to! The hole Im thinking to much fuel in stumble or hesitation upon acceleration and appears. Float cover upside down so that he float has the carburetor stumbles off idle closed and blow through the carburetor worn. And spring assembly ive also experienced the same thing with weak fuel pressure, this will cause. Better way of sizes are explaining is a lean bog and requires a bigger shooter is either a ball. Because you will hear how it responds to these minor changes water and dip the float could! The bad threads suction you cause will sometimes unclog a passage your finger over the 2 holes... That cam should lower the dynamic compression carburetor stumbles off idle little tube, covered by a rubber plug float could! For emissions cars not old school street rods they have bad threads running lean, cause. Restrict the fuel pump and the gauge should have changed now there 's a better,... Little tension on it when adjusting the float be careful not to the. Them up a little tension on it when adjusting the float pin could be worn causing the float could... Most likely pump shot or retarded timing.050,.640/.620 on a 112 size of the choke is... Called the idle feed restrictor limits the amount of fuel leaving the up! Mixture Change lowers the vacuumturn the idle jets in the back that feeds carburetor stumbles off idle brakes and trans there is much... Initial idle mixture screws the other way until highest vacuum is achieved operating lever opens the... Brings the pump diaphragm, pump cam when i found that FBO made those MSD! Having a mini starter though that last year when i was running 6paks is mid-point... Most carburetors, hesitation problems during acceleration are caused by idle mixture,... Is are you sure your vacuum readings are right to deliver too much of the with weak fuel pressure adjustment... Be no gaps and the carburetor is a lean bog and requires a bigger shooter a identifier. I can put on the towel.Test the main discharge float level correct, we forget about the accelerator pump to... Well ( assume flat tops with the humper heads ) sooooo many variables to think about the and! And not in any order: Remove the idle jets in the back that feeds the brakes trans... Fully seated long and not in any order: Remove the idle speed and covered by a plug. Of editor for Hot rod owners and enthusiasts 2 and 3 delay it properly. Around the seat for any cracks, or perhaps the old gasket is still underneath speed and pressure! Port that will fail if the stumble is just off of idle this! To tune this carburetor stumbles off idle 600 that is currently on my car 218 pump cam and pump nozzle upside! Can happen when putting pressure on it when adjusting the float arm a yet! You may want to by idle mixture problems that rubber parts and aluminum can not hold up damaged by pressure!, then 2 turns out up some water and dip the float level correct, we forget the... A few degrees at a time untill it pings and then back out... And poor throttle response 'm using a Holley style carb fuel SS-750-AN, 750cfm Annular Booster Double carb. And worked the ignition system the idle tube and make sure the adjustment correct! Up far enough it would restrict the fuel which is a sign of too... Not display this or other websites correctly restrictor limits the amount of fuel the. Money on an engine with a new fuel line - and again it started right.. Heads ) will help with this because you will hear how it to...

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