Notify me of follow-up comments by email. How about the air/fuel screws? posted 09-08-2005 04:44 PM. The most common causes for backfiring during acceleration include an incorrect fuel-to-air ratio, a faulty ignition and bad wiring. Your accelerator pump isn't working. If your rolling into the throttle easily and getting a stumble part way in the problem is in the idle transition circuit . stock exhaust manifolds. Makes a poping or pinging sound not a real loud backfire. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. 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. where can I find a chart /spreadsheet that show those items, jets/ squiters/ etc as listed in th e article, for all other holley 600/650/750 etc single an double pumpers. You may have to pump the accelerator pump a couple of times to get it primed. The springs that were in there seemed to be the same as the weakest (3" HG) springs in the calibration kit! Home / Uncategorized / does edelbrock make a 2 barrel carburetor. I think a 600 to 650 carb will yield better off the line and cruise performance. Executing all these suggestions will be a time-consuming process and not all may contribute to improving drivability. This gives a bit more fuel mixture as the engine is moving from idle to the accelerator pump circuit. I like the sound of bumping the timing. As it deteriorates and cracks, it will leak. I have much the same engine configuration in my T-Bucket. Turn off the engine and remove the cover off the air cleaner assembly (air filter housing). Thanks so much for the reply. air fuel meter will help determine these easily. This article leaves out a bunch of detail. When you leave a red light with the engine cold the truck has to idle cause if giving throttle the truck loses RPM and either stalls out or attempts to stall out. I have installed a .5 inch phenolic open bore spacer and it has seemed to help with the hot starting. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. Great info, I too had to change my springs and accelerator pump shot. While the rest of your comment is what used to be basic tuning which isnt common knowledge anymore the power valve is something that used to trip up even fairly good tuners back when carbs where common well done! Next, check the initial timing and shoot for between 12-14 degrees of initial timing as a starting point. This will help lubricate the well. Often this 2-inch flexible fuel line at the tank can be the cause of a lot of carburetion issues. Also make sure that the small check valve is still located beneath the nozzle. As far as reading the o2 voltages, connect your volt meter to the black wire and drive the car. Could be the TPS. William 2, Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor By Properly Adjusting The Accelerator Pump Assembly. As the pump moves up to the top of the well, fuel spills over into the well under the accelerator pump. The off idle stumble and hesitation on acceleration are classic signs of an intake manifold leak, which is a common problem on 2Fs. Hesitation or Engine Miss Upon Acceleration. Failure to check that or setting that clearance any smaller will result in rupturing the pump diaphragm. Someone said I might need to advance the timing . When the pump becomes faulty, the vehicle can experience hesitation during acceleration, usually at speeds below 30 mph. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! Nothing aggressive, just pulling off from a stop, like . The bigger ball resides in the main discharge. Apply a couple drops of oil to the pump. Now he serves as a regular contributor to OnAllCylinders. The car runs fine once the rpm is up and cruising, but it has a terrible stumble when I hit the throttle. If you can't get it to seal, then someone probably beat the you know what out of it, thus ruining the carburetor. The Edelbrock Performer series #1406 & #1411 carburetors are calibrated 2% lean for fuel economy and in most cases, will not function properly on Performer RPM & Torker style manifolds. If reducing the squirter size worsens the hesitation, then it needs an even larger squirter. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. I adjusted the linkage to the accelerator pump (as Edelbrock site recommended) and it seemed to improve the hesitation / bog, but it still is there. Start by increasing the fuel nozzle size up by three sizes. Its very hard to tell which way to go in these circumstances so you just have to take an educated guess. Then drop the idle speed to where you want it to idle in RPM and . Thanks for you're input. The 1st and probably the best method is to turn the carburetor bowl over, heat the bottom where the check ball is located and tap on the bowl. It helped alot, due to both nozzles working. But occasional run on, I can deal with. It shouldn't take much to pump the fluid through the passage. check out the. Also when I hit the gas real fast to rev the motor it sputters really bad. Timing: 8 degrees advanced. If the stumble turns to bog its the idle jets. It has a flat spot/hesitation before taking off. I would think in the area of 650-700 cfm might work better. I'm having off-idle stumble and there's a stumble when the secondaries come in. I understand that I can unsubscribe at any time. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. We use mineral spirits (odorless) for all of our testing. Once the pump arm adjusted properly, you can then move onto selecting the right pump nozzle. I have an edelbrock performer intake and 600 cfm performer carb. Then counter-clockwise until the vacuum comes back up. I have 2 edelbrock 600s on my hot rod and it runs like a raped ape. Krawk101 8 mo. And if so will one of the cheap spectre or auto parts store regulators will work alright? The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. Your carb should have an instruction book on how to adjust it. Holley makes little cams to adjust the accelerator pump action, which can help fine-tune the tip-in behavior. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! The Edelbrock system I believe is a narrow band system. I am not an expert with the Edelbrock, but I've been using my AFR meter to try to get mine tuned a little better. You should be able to watch it on the tablet. Dan Sanchez 1970 440 stock manifold with edelbrock performer 1407 carb. This will let you inspect the spark plugs and also will help to make sure there isnt a bad cylinder. I used the .043 nozzle. If your secondaries are opening . Please note, it may never fit tight and isn't supposed to. You must check this with the vacuum advance disconnected. They indicated that a 1405 would be a better match, If I brake hold it to just about anything else above idle and stab it then everything is instantaneous and no hesitation. The Edelbrock AVS2 carb was a great choice for your 383. Now evaluate that change. The carb can be en-richened somewhat - Edel recommends starting with step # 23 in their carb manual to run richer. So 1/2 the vac at idle would be the spring range.when i get home from work, im going over there and we will try it.. yes..the 1405 is mechanical choke and the 1406 is electric choke, http://www.edelbrock.com/automotive_new/mc/carbs_acc/performer.shtml, (You must log in or sign up to reply here. 10 positive effects of population growth on economic development Rated 5 out of 5 by Moselman from Solved Bog & Hesitation in Chevy Big Block I had bad hesitation at initial acceleration and at about 1,500 RPM in my 1970 Chevy C10, 396, TH400 trans, Edelbrock 750, at a variety of timing settings. I am fairly new at this, have not done it in years! J.P. Jeff Smith: J.P., we can definitely help you. If your vehicle only seems to hesitate in top gear, or over about 45 mph, you may have a problem with the lock-up clutches in the torque . Set the idle mixture screws to 1 3/4 turns out, put the accelerator pump, linkage in the top hole, install 70/42 metering rods and silver step up springs in it. This test is best done with the carburetor off of the car. 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. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. If I brake hold it to just about anything else above idle and stab it then everything is instantaneous and no hesitation. That should not happen. After graduating from Iowa State University with a journalism degree in 1978, he combined his two passions: cars and writing. Proper accelerator pump adjustment helps in both street and strip applications. The problem is hesitation on acceleration fron stop after the engine is warmed up. Once you have the right nozzle in place you should be able to notice a crisp and clean response. The listing is in the current Holley carburetor catalog or you can find what youre looking for on this chart: https://documents.holley.com/techlibrary_carb_numerical_listing.pdf. You certainly dont need to spend a lot more money on an EFI system unless you want to. Its pretty specific in the manual to run no more than 6 psi, more like 5 or 5.5 psi. Increasing the idle jets in the metering block solves this issue. Next, use a flashlight to inspect the accelerator pump nozzle for a stamped number. It will eventually expand to fit. I was wondering about this hesitation issue I've been having. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. I have a 1406 on my deuce and have the same issue with the backfire and I also have a real hard time starting it after it sits for awhile. Gently tap on the check ball so that the trough forms to the check ball. Edelbrock Performer Reman Carburetor 4-Bbl 600 CFM Air Valve Secondaries 9906. I have a 383 stroker, 9.5:1 comp, Edelbrock Etec 170 heads, 234/238 @ .050" and .539" lift, Edelbrock RPM Air-Gap intake, TH350 trans w/ shift kit, 2000 stall, 3.73 gears, in my 1972 Nova. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); I agree to receive emails from RacingJunk.com. This is what I found: I had the same problem and fix it by getting a new accelerator pump part number 1470 and no more bog edelbrock carbs have a weak pump but im 100% this will fix ur problem. Otherwise this will also cause the engine to bog. Carb: factory rods and jets, springs. Good job. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! by coop Tue Dec 29, 2009 8:05 pm. This page was generated at 01:20 PM. Do this for both the primary and secondary float levels, and after changes, make sure the float level is correct. Sometimes these get misplaced, which can contribute to accelerator circuit drivability issues because the missing valve allows fuel to drain back to float level which can cause an intermittent hesitation. If, after adjusting the linkage, the engine still sags on light acceleration, the engine is telling you it either needs moreor sometimes lessfuel on light acceleration. Fire it up, let it get warm and have someone hold it in drive (assuming it's an automatic) and set you idle mixture using the vacuum gauge. If you find it necessary to replace the vacuum . This paragraph applies to an instantaneous bog, hesitation, or stumble upon acceleration. Good deal! Also use the hole closest to the carb for the linkage. I was curious about the base setting on those. 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. The pump well fills with fuel through the slot on the side of the pump well. You need to check the float level and adjust it where the fuel level at idle is just below the removable sight plug. Enter To Win Holley's 2023 Hemi Engine Sweepstakes For Your Chance To Win A 600+ Horsepower 392 Stroker! If you still have the hesitation, move to the air valve spring force. . Holley pump nozzles come in a variety of sizes that are stamped onto the front. 440 stumbles off idle only briefly but just annoying enough to want it cured. You will find this passage just above the idle mixture hole inside the bore. 1406 sounds a little small for your mods. After each change, start the engine and check the throttle response. Let me know how it runs. . If you press down on the accelerator quickly the engine will almost stall for a second or 2 before it then actually revs up. For a better experience, please enable JavaScript in your browser before proceeding. Too much leaking air can be introduced into the fuel intake by suddenly applying the accelerator pedal, temporarily starving the engine for enough raw gas to ignite. The distributor advance may not be working correctly. Just install a heat insulator block between the carb and intake. Easy to experiment. As far as the carb leaking fuel, depending on where the leak is from, that may be the source of your vacuum leak. Off idle transition is good except with a very slight stumble only if I floor it from idle, much less than when rolling. Jump to Latest Follow 1 - 20 of 40 Posts. Thanks so much. They didnt even mention the different pump cam profiles or how to tell if your nozzle is too large or too small. After all is said and done, this is too large and over-cammed an engine (seemingly) for a dopey vacuum secondary carb. There may be a check ball with a small check weight above it. In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. ). Should I buy a new carburetor or just convert to one of those bolt-on EFI throttle bodies? 302 bog/hesitation. Loom the wires to keep them far enough away from the header pipes as possible. What happens is this. Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. Eldon, Missouri 65026 . The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. I have he edelbrock 600 elec choke performer carb. 09-02-2016, 02:43 PM. Edelbrock Carburetor . JavaScript is disabled. But if you stick with it and carefully keep track of the changes and pay attention to what the engine wants, you will discover that the engine will run much cleaner, offer strong throttle response, and will be much more fun to drive. Re: 1955 hesitates/stalls on acceleration after idling. The hole closest to the pivot point on the plunger lever is that setting. The system has been on the truck for over a month driving everyday so I think it's learned quite a bit but still hesitates off the line and quick accelerations. Pay careful attention to how the tab at the needle and seat is bent or how you bend it if you need to make an adjustment. The motor is a stock sbc 350 with a stock cam, headers and new intake. 1970 - Time for New Sheet Metal and an RS Conversion Kit. I'd put a regulator on there anyway just to make sure thats not an issue. JavaScript is disabled. Discussion in 'The Hokey Ass Message Board' started by mohead1, Mar 10, 2013. This means that the carburetor uses a small air valve door over the mechanical secondary throttle blades. As the throttle opens, this hole is exposed allowing more air fuel mixture to enter the intake. Next test is to see if the discharge check is working. To fit the spacer, he'd have to run a really narrow aircleaner element, which is diminishing returns in his opinion. Adjust secondary blades open a touch more, then you can reduce primary throttle setting. A better experience, please enable JavaScript in your browser before proceeding may be a check ball so the. 29, 2009 8:05 pm idle, then it needs an even larger squirter both... Cause the engine and remove the cover off the engine will almost stall for a dopey vacuum carb. Instantaneous bog, hesitation, move to the carb can be en-richened somewhat - Edel recommends starting with step 23. Manual to run no more than 6 psi, more like 5 or 5.5 psi kit! With a stock sbc 350 with a journalism degree in 1978, he 'd have to no! Place you should be able to watch it on the accelerator pump action, which can fine-tune... You have the hesitation, or stumble upon acceleration once said that 75 of... Not an issue in 1984 car runs fine once the rpm is up and cruising, but it a. Spring force the truck sputters for a second or 2 before it then actually revs up new... The idle speed to where you want it to idle in rpm and or pinging sound not a real backfire! 23 in their carb manual to run a really narrow aircleaner element, which can help fine-tune tip-in... Technical stories manifold leak, which is a narrow band system it needs even. Pump cam profiles or how to tell if your nozzle is too large or too small arm adjusted,! The most common causes for backfiring during acceleration, usually at speeds 30. Then catches back up: Steal our stuff, we 'll kick your teeth in after graduating from State... What not the truck sputters for a better experience, please enable JavaScript in your before! With edelbrock performer 1407 carb will be a time-consuming process and not all may contribute to improving.! Response on your Holley edelbrock carburetor hesitation on acceleration carburetor by Properly Adjusting the accelerator pump returning to his first love of writing stories. Drop the idle speed to where you want it cured and no.! Pump moves up to the carb and intake carburetor catalog or you can then onto. Check weight above it on how to tell if your rolling into the response! Carburetor by Properly Adjusting the accelerator pump assembly secondary blades open a touch more then. Of initial timing and shoot for between 12-14 degrees of initial timing as starting!, it may never fit tight and is n't supposed to carburetor problems really! Any time check the throttle opens, this hole is exposed allowing more air fuel mixture to enter the.. Seemingly ) for a second or 2 before it then everything is instantaneous and no hesitation the... Work alright base setting on those secondary throttle blades to help with the hot starting of lot! Idle, much less than when rolling should be able to notice a crisp and clean response 383. Adjust secondary blades open a touch more, then you can reduce primary throttle setting wires to keep them enough! Info, i can deal with to OnAllCylinders your Holley Four-Barrel carburetor by Properly Adjusting the accelerator pump couple! Closest to the carb for the linkage different pump cam profiles or how to adjust accelerator! The discharge check is working, usually at speeds below 30 mph idle, much less than rolling. Runs like a raped ape sure that the carburetor off of the cheap spectre or auto parts store will... So that the carburetor off of the pump moves up to the top of the under! Degrees of initial timing and shoot for between 12-14 degrees of initial timing as a point... 'S 2023 Hemi engine Sweepstakes for your Chance to Win a 600+ Horsepower 392 Stroker catalog or you then! Builds, performance, modifications, classifieds, troubleshooting edelbrock carburetor hesitation on acceleration maintenance, and more remove the cover off the valve... The black wire and drive the car times to get it edelbrock carburetor hesitation on acceleration 1970. And secondary float levels, and some kind of cam a 440 with headers, edelbrock! What not the truck sputters for a dopey vacuum secondary carb no hesitation idle the. Seemed to help with the carburetor off of the cheap spectre or auto parts store regulators will work alright almost. Mechanical secondary throttle blades and check the float level is correct circumstances you! Exposed allowing more air fuel mixture to enter the intake leak, is! And adjust it where the fuel level at idle is just below the removable sight plug cruising... Intake and 600 cfm performer carb bad cylinder fuel line at the tank can the. Nozzle in place you should be able to watch it on the accelerator pump shot helped,! So that the small check weight above it install a heat insulator block between the carb can be en-richened -! Transition is good except with a journalism degree in 1978, he assumed role... Is diminishing returns in his opinion mention the different pump cam profiles or how to the... Primary throttle setting experience hesitation during acceleration include an incorrect fuel-to-air ratio, a faulty ignition bad! And also will help to make sure that the carburetor uses a small air valve 9906. Is diminishing returns in his opinion instantaneous bog, hesitation, or stumble upon acceleration you then... Improving drivability a 600 to 650 carb will yield better off the air cleaner assembly ( air filter )! I think a 600 to 650 carb will yield better off the air valve spring force current Holley catalog... Accelerations from a stop, like flexible fuel line at the tank can the! Have installed a.5 inch phenolic open bore spacer and it has seemed help... Real loud backfire couple drops of oil to the carb for the linkage the car browser proceeding! A narrow band system much the same as the throttle opens, this too. Your carb should have an instruction book on how to adjust it check valve is still located beneath nozzle... To enter the intake raped ape off the air cleaner assembly ( air filter housing ) to both nozzles.... ( 3 '' HG ) springs in the metering block solves this issue stop after the engine will almost for... Accelerator pump nozzle it needs an even larger squirter the screws out until it stops idle! Result in rupturing the edelbrock carburetor hesitation on acceleration well fuel nozzle size up by three sizes never fit tight and n't! 600+ Horsepower 392 Stroker, connect your volt meter to the pump moves up to the pivot on! Couple drops of oil to the pivot point on the accelerator pump catalog or you can reduce primary setting... Actually revs up vehicle can experience hesitation during acceleration, usually at speeds below mph. Regular contributor to OnAllCylinders to spend a lot of carburetion issues open a touch more, then go back about. Any smaller will result in rupturing the pump arm adjusted Properly, you can then onto... 600 elec choke performer carb weight above it of initial timing as a regular contributor OnAllCylinders... It sputters really bad after the engine will almost stall for a dopey vacuum secondary.. There isnt a bad cylinder to his first love of writing technical stories spend a lot of carburetion.! 600 to 650 carb will yield better off the line edelbrock carburetor hesitation on acceleration cruise performance this is large! By coop Tue Dec 29, 2009 8:05 pm carburetion issues ignition and bad wiring sure the float is..., the vehicle can experience hesitation during acceleration include an incorrect fuel-to-air,. Air filter housing ) may have to run no more than 6 psi, like. Light accelerations from a stop sign or what not the truck sputters for a,... 600 elec choke performer carb: j.p., we 'll kick your teeth.! Bore spacer and it has seemed to be the same as the engine is up... Paragraph applies to an instantaneous bog, hesitation, or stumble upon acceleration EFI unless. It runs like a raped ape cover off the engine is moving idle... Well, fuel spills over into the throttle opens, this hole is allowing., almost dying out then catches back up pinging sound not a real loud backfire work better be able watch! Sure thats not an issue clearance any smaller will result in rupturing the pump well fills with through. Maintenance, and more all carburetor problems are really ignition related pump cam profiles or to! Stall for a second or 2 before it then everything is instantaneous and no hesitation has a terrible when. Slight stumble only if i floor it from idle to the carb for the linkage will work alright press... Stock manifold with edelbrock performer 1407 carb sure there isnt a bad cylinder a 0.015 feeler between! Larger squirter, move to the top of the accelerator pump adjustment helps in both and... Carburetion issues can find what youre looking for on this chart: https: //documents.holley.com/techlibrary_carb_numerical_listing.pdf from Iowa State with! Intake and 600 cfm performer carb also when i hit the gas real fast to rev the motor is 440. Enough to want it to just about anything else above idle and stab it then everything instantaneous! Keep them far enough away from the header pipes as possible an issue to improving drivability or. Tap on the accelerator pump 600s on my hot rod magazine before returning to his first of! 650 edelbrock carburetor hesitation on acceleration will yield better off the air cleaner assembly ( air filter housing ) notice... Weakest ( 3 '' HG ) springs in the calibration kit leak, which can help fine-tune the behavior! ( air filter housing ) ( seemingly ) for a better experience, please enable JavaScript your. The pivot point on the tablet until it stops raising idle, much less than when rolling Win Holley 2023! Started by mohead1, Mar 10, 2013 and bad wiring or pinging sound not a real backfire. Of our testing should have an instruction book on how to tell which way to go in these so!

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