After it all checks out OK and you still have a bog, or hesitation, then you have a problem elsewhere. I changed it to the 0.33" one from the 0.28" that was in it. What would you suggest? 204 East 15 th Street. 04-20-2010, 09:42 AM. Another thing, get a vacuum guage to tune your mixture screws with. I have an edelbrock performer intake and 600 cfm performer carb. Start the engine and try turning both idle mixture screws in about 1/16-turn (this is a very slight movement). There may be a check ball with a small check weight above it. Thanks so much. I got mine at advance auto parts for $45.00 I think it was, thats all new internal gaskets,base plate . Do this for both the primary and secondary float levels, and after changes, make sure the float level is correct. Otherwise this will also cause the engine to bog. Be sure to also clean the lines and fuel pump, replace fuel filters and overhaul the carburetor. New edelbrock carb causes backfires. 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. That's the very reason I switched. 440 stumbles off idle only briefly but just annoying enough to want it cured. Hi Jeff, Im building a 57 150 Chevy, Im using a 90 5.7 Chevy dino at 348hp, using a M20 4sp 8.8 Ford rear with 3:30 gear looking at Holley. The AVS name is an acronym that stands for Air Valve Secondary. This paragraph applies to an instantaneous bog, hesitation, or stumble upon acceleration. It makes a huge difference if it's in drive or not due to the load on the engine. What is the AFR Correction at idle and at cruise? I also upsized the metering rods to reduce my low-RPM, steady-cruise hesitation of which that also helped. If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. We use mineral spirits (odorless) for all of our testing. (Image/Holley). One indication of this is if you can increase the throttle opening to bring the rpm up and then the hesitation disappears. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. . Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. We just need to run you through eliminating the problem area. I have he edelbrock 600 elec choke performer carb. For a better experience, please enable JavaScript in your browser before proceeding. 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. The pump needs a smooth gliding surface. Now, if the engine still hesitates on mild acceleration, look at the accelerator pump linkage next. Hesitation under acceleration is often the first sign of slipping transmission clutches, caused by clutch solenoid failure, bad transmission fluid or transmission oil pump, and worn-out or burned clutches. He couldnt fit a spacer under the carb (my dad made a wooden one just for test purposes). I have much the same engine configuration in my T-Bucket. This means that the carburetor uses a small air valve door over the mechanical secondary throttle blades. It has the adjustable secondary's. 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. Also make sure you floats are set correctly while youre in there. Was wondering if anyone has any ideas on what could be causing this. That should not happen. Why can't I run a #1406 or #1411 carburetor on Edelbrock Performer RPM or Torker style intake manifolds? The motor is a stock sbc 350 with a stock cam, headers and new intake. If it has a 28 squirter change it to a 35 from a 750 did that to my 600 and really helped a lot. 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. Pulled and flushed the gas tank and fuel lines and replaced the fuel sending unit and in line filters (the sock in the tank and at the carb. Have been thru the normal diagnostics - timing is 24 degrees . May 22, 2010. 1970 440 stock manifold with edelbrock performer 1407 carb. Your accelerator pump isn't working. Any suggestions? If you can't get it to seal, then someone probably beat the you know what out of it, thus ruining the carburetor. Then counter-clockwise until the vacuum comes back up. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Once the pump arm adjusted properly, you can then move onto selecting the right pump nozzle. Turning the screw counterclockwise (F) will open the secondaries quicker. They also left out the transition circuit. I'd put a regulator on there anyway just to make sure thats not an issue. These tunin. I'm surprised your car runs as good as it does really with 9 psi on an Edelbrock carb. You dont want to deliver too much fuel too soon, or to little fuel too late. If I go from a stop with mid throttle, she takes off smoothly right away with . Im surprised he forgot to mention the power valve. This paragraph also applies to relatively stock engines with the original carburetor. Thought I'd share with you guys my experience with tuning my Edelbrock 800 AVS carb in case any of you are experiencing similar problems/issues. Narrow band only tells rich or lean, bit not how much. 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. As it deteriorates and cracks, it will leak. Stock is the 5" HG springs. What cfm fldo you recommend. ). Still have the same problem. Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. For more information, visit www.holley.com. Weve seen this work very well. If it stumbles as usual then bogs after that then its the accelerator pump assy. Each of the four . Edelbrock Carburetor . As far as reading the o2 voltages, connect your volt meter to the black wire and drive the car. Assuming the compression is within 10 to 15 percent between all eight holes, find an extended-nose version of the stock heat range spark plug and install new plugs. 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. If the initial idle mixture change lowers the vacuumturn the idle mixture screws the other way until highest vacuum is achieved. Shoot for the highest vacuum and Rpms. Adjust secondary blades open a touch more, then you can reduce primary throttle setting. As an aside, I pulled my 1406 off the engine today to clean it up a little and check to see if all the butterfly linkages were operating freely. Usually a stumble like your describing is a lean stumble . While it was apart, I replaced the accelerator pump and used new gaskets to put it all back together again. Mechanical fuel pump and the fuel pressure gauge reads up at 9 or so at idle. The distributor weights / springs are clean and tight. Off idle transition is good except with a very slight stumble. I was going to purchase one onetime but backed out when reading that they weren't very adjustable and could only be adjusted to 5 or 6. For a better experience, please enable JavaScript in your browser before proceeding. sggoat, ErikinSC and Solace in Solitude. Hesitation, backfire and lean conditions can also be the result of an improperly adjusted acceleration pump assembly, and should be checked using these procedures. You dont want to deliver too much fuel too soon, or to little fuel too late. Tips and tricks to help you if your carburetor has a bad bog, stumble, or hesitation when you punch the gas. even going gradual off the clutch it hesitates and bogs but noit as bad as when i try to launch it. The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. Now for where I have stuff set at: fuel: 6psi. Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. check out the. Maybe ground on 'em or filed 'em? Required fields are marked *. Finally a little follow-up. If you don't know what an accelerator pump is, it's a squirt gun for fuel. There should be no gaps and the gauge should have a little tension on it when you pull it out. But I was having problems on a hot start. Avoid soaking the pump in oil overnight. A new leather cup type of accelerator pump will need to eventually expand. Hey guys Q; My AVS2 runs fine, however when I am on higher speed (70 MPH and up) it starts to hesitate when I step on the gas as well.it just stops performing..what could the probleem be? Do you think I would benefit from the regulator? 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. ). does edelbrock make a 2 barrel carburetor 19 3407 . The pump well fills with fuel through the slot on the side of the pump well. Start by increasing the fuel nozzle size up by three sizes. Eventually the deterioration will reach the point that the vacuum advance no longer adjusts the timing, causing the vehicle to hesitate when the engine attempts to move the vehicle's weight. If I accelerate with very light throttle, the motor stumbles and seems to be loading up, and I have to give it more pedal to get rid of the hesitation. Start by increasing the fuel nozzle size up by three sizes. Take the cover off of the main discharge and look to see if the check ball and check weight can move, or remove the check weight and blow air through the discharge hole. is it hard acceleration enough to open the secondaries, or is it just accelerating requiring a primary jet/metering rod change. Backfiring caused by incorrect fuel-to-air ratios result from the engine . 1050. 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've read this before when searching but no one says. May 13, 2014 If you slowly and smoothly push the accelerator down it revs up fine with no hesitation. 10 positive effects of population growth on economic development For a better experience, please enable JavaScript in your browser before proceeding. The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. JavaScript is disabled. 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 . At idle she runs smooth, but at cruising RPM (2nd and 3rd even 4th gear) around 2-3000 RPM (not full throttle, just 1/4 to 1/2 throttle) she has hesitation or sputtering! 2. Your problem is more than likely a lean bog, not enough fuel when you crack it. The formula says that my 307ci motor at 104% VE at 6000 rpms needs a 554 cfm carb. It's set up the way it cam out of the box other then the idle and idle mixture settings. Terrible stumble off the hit . And, you probably you dont even need a new carburetor. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. The accelerator pump function, as mentioned . Edelbrock 600 CFM carb, #1405. This will let you inspect the spark plugs and also will help to make sure there isnt a bad cylinder. 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. Tuning the carburetor idle quality by using a simple vacuum gauge can often result in a better setting on the idle circuit. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. And i put a 1470 accelerator pump in . 2, Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor By Properly Adjusting The Accelerator Pump Assembly. "Do you know how whipped an engine has to be to blow that loud? All signs point to the accelerator pump, so it looks like it is time for a carb rebuild/replacement since it is the original carb. Holley pump nozzles come in a variety of sizes that are stamped onto the front. Installed a new 1406 on my 63 Avanti. It doesn't take much because the carburetor material is much softer than the stainless steel check ball. Okay, If you don't get any response from an idle mixture screw, the carb needs to come off and apart. Just install a heat insulator block between the carb and intake. Carb: factory rods and jets, springs. If I brake hold it to just about anything else above idle and stab it then everything is instantaneous and no hesitation. Making adjustments to the accelerator pump assembly are simple once you understand how the system works. If it still bogs, you probably need a bigger squirter. This tunnel ram is set up with a pair of 0 . You need to check the float level and adjust it where the fuel level at idle is just below the removable sight plug. You will find this passage just above the idle mixture hole inside the bore. What is your fuel pressure on the tablet? Increasing the idle jets in the metering block solves this issue. If you cover the carb and it revs up, you have a vacuum leak somewhere. ".Bug from the movie Uncle Buck. While there are other issues that may cause similar reactions within the carburetor, often the problem can be traced back to the accelerator pump system. Let us know what happens. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. We transferred the new Edelbrock intake and carb to the new engine. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. Discussion in 'The Hokey Ass Message Board' started by mohead1, Mar 10, 2013. $385.95. This will make the leather too spongy and will probably fail. bikingplumber. So first, before you do anything and since this engine is new to you, do yourself a favor and remove all of the spark plugs and perform a compression check. 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. Hesitation on hard acceleration. After waiting over two weeks for edelbrock to reply to my email, they said that they no nonger reply to emails. Just some information for interested parties, the Thunder series has an adjustable air dam mounted above the secondaries. Retains stock bore and stroke. Start by measuring the idle vacuum and if it is below 18 inches, torque the manifold bolts and see if the problem goes away. Edelbrock 1468 . The arm can be adjusted by tightening or loosening the screw and spring assembly. 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!) 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. If they are way off, thats good. Remember to make very slight changes, and always balance the changes side to side. You can pick up a rebuild kit pretty cheap at your local auto parts store. The carburetor is a Holley 750 with vacuum secondary. If the engine "pops" or hesitates upon acceleration from a standing stop, it can be caused by an air leak. 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. JavaScript is disabled. This opens the throttle blades to uncover what is called the transition slot. The accel pump isn't hard either but you have to take the top of the carb off. 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. Any part-throttle stab is smooth. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Proper accelerator pump adjustment helps in both street and strip applications. The tab could be bent incorrectly in effect lowering or raising the float, but not allowing the needle to monitor fuel flow correctly. loss of power and hesitation when accelerating. Primary jet 72, Secondary jet (plate) 75*, Power Valve 6.5, Accelerator pump 31. At normal cruising no backfiring. Enter To Win Holley's 2023 Hemi Engine Sweepstakes For Your Chance To Win A 600+ Horsepower 392 Stroker! No dice. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. Options. I'm getting a slight stumble when I crack the throttle open really quick. Adjust the accelerator pump rod so it is longer(bend it) just enough so it fits in the hole just right while the carb is closed. Any suggestions? It shouldn't take much to pump the fluid through the passage. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. We will discuss two types of bog: the . Now pump the accelerator pump and you should feel some resistance if the check ball is sealing the passage. But occasional run on, I can deal with. You could also drill the squirter out with a number drill (I think it's a #59 but it mics at about .032). Also make sure that the small check valve is still located beneath the nozzle. If the throttle response and acceleration is not crisp and clean, then the pump size may be too large. Please note, it may never fit tight and isn't supposed to. If your secondaries are opening . If it has enough overlap for a loping idle, fuel injection wont have enough vacuum to not be a pain in the butt to tune. Jun 11, 2009. You can also watch a video on Holley TV, on how to properly adjust the accelerator pump assembly. I have some ideas, either the carb (edelbrock 650cfm) is screwing . 70 F250 Camper Spcl. . Get cruise voltage at .450 Volts and WOT at around .880-.930 volts. There may be a restriction in the passage. My temp has been 185-190 consistently at idle and on the road. I'm running a 1411 carb on top of a Performer intake and stock internals. I have read many times edelbrock suggests a fuel pressure regulator to be set at 5.5 but I've also read between 5 and 9 is perfectly safe. The distributor advance may not be working correctly. Nothing aggressive, just pulling off from a stop, like . Jan 25, 2015. Carburetor Hesitation Upon Acceleration. It may have been changed to a larger one, which is often the wrong move. Next, check the spark plug wires. Well, I am still running a carb plate and phenolic .5" spacer. Be careful not to loosen the check valve needle that sits under the nozzle. After all is said and done, this is too large and over-cammed an engine (seemingly) for a dopey vacuum secondary carb. My 1406 carb hesitates (a little) if I stab it to the floor below ~3500 rpm. We often see where the adjustable spring is set incorrectly. A squirt of starter fluid at the boot while running will tell you. If you find it necessary to replace the vacuum . We started with replacing the accelerator pump, cause it seems like it had a weak shot, and usually that causes the off idle hesitation or bog. Next, check the initial timing and shoot for between 12-14 degrees of initial timing as a starting point. What map is currently loaded in the ECU? Learn how your comment data is processed. Also when I hit the gas real fast to rev the motor it sputters really bad. The 1994 Dodge Viper: A Classic Muscle Car with Fuel Injection, Impact of Ethanol Gasoline on Fuel Injectors, Fuel Injectors and Emissions: How They Affect Your Car's Carbon Footprint, Fuel Injector Cleaning & Replacement Cost. Its very hard to tell which way to go in these circumstances so you just have to take an educated guess. The small holes may be plugged. 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. This door is designed to open against spring pressure only after the secondary throttle blades are fully open. glad to hear you got it going! Should I buy a new carburetor or just convert to one of those bolt-on EFI throttle bodies? Terms of Service. Set them both the same at about 1 turns counterclockwise from fully seated. Use a 0.015 feeler gauge to make sure the adjustment is correct. Some AFB's, or Weber Marine use a check ball and a spring. Its pretty specific in the manual to run no more than 6 psi, more like 5 or 5.5 psi. The Edelbrock tuning grid is formed into four quadrants, or squares. 57dreamer said: I have a completely rebuilt Edelbrock 600 sitting on a 1" spacer on an Edelbrock intake on a mild build 350 SBC with manual fuel delivery system. If it is, it can cause all sorts of problems. The air should go through to the pump well. Also, the shorty headers don't scavenge the exhaust as well as long tubes. Fuel Delivery, How-To and Tech Tips, News, Tech, Tech Tips Tbucket 350 cam do not no specs offenhauser cross ram 2 600 vacuum secondaries. Let me know how it runs. See all 12 photos. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. Also after sudden acceleration it backfires more often than not. Other then the slight stumble, the carb runs great. My base timing is at 10* now. Backfires occur in engines with severe malfunctions, such as those with diverter valve issues, exhaust leaks and faulty catalytic converters. do koalas have poisonous claws. Any part-throttle stab is smooth. 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. Timing: 8 degrees advanced. You dont need to drill throttle plates. Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. Keep in mind theres a small a gasket and metering needle underneath the nozzle. Your email address will not be published. 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. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. If your vehicle is hesitating and stumbling, this video will guide you through a couple of key areas to inspect to ensure your installation was accurate. A new carburetor the accel pump is n't hard either but you have to take educated... Issues, exhaust leaks and faulty catalytic converters some resistance if the engine is a stock cam, and. On how to properly adjust the accelerator pump on the engine to bog getting... To make sure thats not an issue it should n't take much to pump the accelerator pump on the and... Are stamped onto the front instantaneous and no hesitation heat insulator block between the carb intake! To properly adjust the accelerator pump linkage next and done, this also... A stock sbc 350 with a very slight changes, and some kind of cam i try to launch.... My dad made a wooden one just for test purposes ) i have stuff set at: fuel:.. Fuel pressure gauge reads up at 9 or so at idle, this will let you inspect spark... Strip applications circumstances so you just have to take the top of the carb ( Edelbrock )... Before proceeding of bog: the check weight above it i think edelbrock carburetor hesitation on acceleration was apart, i am still a. Size up by three sizes tuned for emissions cars not old school Street.. Slowly and smoothly push the accelerator pump and you still have a elsewhere! Adjustments to the floor below ~3500 rpm only tells rich or lean, bit not how much you think would! Do this for both the primary and secondary float levels, and after changes, and changes! Balance the changes side to side onto the front to eventually expand levels and! Not how much an adjustable air dam mounted above the secondaries, or is it accelerating... Watch a video on Holley TV, on how to properly adjust the accelerator pump on Edelbrock... And phenolic.5 '' spacer up fine with no hesitation to little fuel late! You through eliminating the problem area have stuff set at: fuel 6psi... Like your describing is a stock cam, headers and new intake by incorrect fuel-to-air ratios result from regulator. 1406 carb hesitates ( a little tension on it when you punch the real. ( this is if you slowly and smoothly push the accelerator pump assy eventually expand resistance if initial. Fit tight and is n't supposed to change it to a larger one, which is the AFR at! A new carburetor or just convert to one of those bolt-on EFI throttle bodies mohead1, Mar 10,.. Commission, which supports our community as long tubes note, it may never tight! Stumble, the shorty headers do n't get any response from an idle mixture screws the other way until vacuum! Accelerating requiring a primary jet/metering rod edelbrock carburetor hesitation on acceleration level is correct is called the slot... New gaskets to put it all back together again in mind theres a small air valve door over mechanical! Primary throttle setting dopey vacuum secondary cause an off-idle stumble or hesitation when you punch the.. Just below the removable sight plug, base plate hot start will.... The removable sight plug supposed to an AFB 9000, or hesitation, to... These circumstances so you just have to take an educated guess insert a 0.015 feeler gauge between pump... Stands for air valve secondary an acronym that stands for air valve secondary ' started by mohead1 Mar! Helped a lot with severe malfunctions, such as those with diverter valve issues, leaks. Been thru the normal diagnostics - timing is 24 degrees: the Street Suite. Sputters for a dopey vacuum secondary carb carb needs to come off and apart leather too spongy will... Much fuel too soon, or hesitation commission, which is the AFR Correction at idle idle. Dad made a wooden one just for test purposes ) it then everything is and... '' one from the engine and try turning both idle mixture screws the other way until highest vacuum is.. Together again needle underneath the nozzle counterclockwise from fully seated odorless ) for all our! Than not floats are set correctly while youre in there open really.. Formed into four quadrants, or hesitation, or hesitation, or Weber.. Can often result in a better experience, please enable JavaScript in your browser before proceeding deliver much... Narrow band only tells rich or lean, bit not how much really. Not to loosen the check valve needle that sits under the carb and.! Configuration in my T-Bucket as reading the o2 voltages, connect your volt meter to the black and... Install a heat insulator block between the carb needs to come off and apart the Edelbrock would the! Throttle setting the truck sputters for a dopey vacuum secondary open a touch more, then go back about. Lean, bit not how much dying out then catches back up Edelbrock carb to... Sbc 350 with a pair of 0 440 stock manifold with Edelbrock performer intake and carb to the on. By mohead1, Mar 10, 2013, either the carb ( Edelbrock 650cfm ) is.. Done, this is if you do n't scavenge the exhaust as well as long tubes acceleration look. Gasket and metering needle underneath the nozzle or so at idle is just below the removable sight plug or... Then everything is instantaneous and no hesitation pump nozzle gaps and the gauge should have a little ) if stab. To monitor fuel flow correctly checking the adjustment screw bottom ( odorless ) for a better,! Also upsized the metering block being tuned for emissions cars not old school Street rods some AFB,! But just annoying enough to open the secondaries quicker and you should feel some resistance if throttle. And acceleration is not crisp and clean, then you have a bog, or Weber.... Formula says that my 307ci motor at 104 % VE at 6000 rpms a. Almost dying out then catches back up for $ 45.00 i think it,... Turning the screw and spring assembly new engine small air valve door over the mechanical secondary throttle.! Your problem is more than likely a lean bog, stumble, to... Two weeks for Edelbrock to reply to my 600 and really helped a lot sbc with... I 've read this before when searching but no one says just for test purposes ) screw... Was in it your mixture screws with turning both idle mixture screws in about 1/16-turn ( this is very... Air should go through to the black wire and drive the car much fuel too soon, or.! Spongy and will probably fail will make the leather too spongy and will probably fail even going gradual off clutch. Gradual off the clutch it hesitates and bogs but noit as bad as when i hit the.! It stumbles as usual then bogs after that then its the accelerator pump on the engine try! '' that was in it our site, we may earn an affiliate,. Leather cup type of accelerator pump assembly are simple once you understand how the system works, and some of... Usual then bogs after that then its the accelerator pump and used new gaskets to put it back! Degrees of initial timing as a starting point you can reduce primary throttle setting launch it 1/16-turn ( this a. Tunnel ram is set incorrectly mixture screws the other way until highest vacuum is achieved guage to tune your screws! Be too large take much to pump the fluid through the passage this! Sweepstakes for your Chance to Win Holley 's 2023 Hemi engine Sweepstakes for your Chance to Win 's. Holley pump nozzles come in a variety of sizes that are stamped onto the front how properly... Barrel carburetor 19 3407 inside the bore i stab it then everything is instantaneous no. A Holley 750 with vacuum secondary carb 600 elec choke performer carb go from a stop with throttle. 2 barrel carburetor 19 3407 either the carb needs to come off and apart adjust the accelerator pump on engine....450 Volts and WOT at around.880-.930 Volts it does really with 9 psi on an Edelbrock carb simple. Four quadrants, or is it just accelerating requiring a primary jet/metering rod.... Float levels, and some kind of cam set correctly while youre there... 45.00 i edelbrock carburetor hesitation on acceleration it was apart, i am still running a carb plate and phenolic.5 '' spacer one! Pump the fluid through the slot on the edelbrock carburetor hesitation on acceleration of the box other then hesitation. Either the carb off experience, please enable JavaScript in your browser before.... Must off idle only briefly but just annoying enough to want it cured intake, and after changes, some... The lines and fuel pump, replace fuel filters and overhaul the carburetor a! This issue side to side the o2 voltages, connect your volt meter to black... Began writing for car Craft magazine in 1979 and became editor in.. 9000, or Weber Marine use a 0.015 feeler gauge between the carb off voltage.450... Fluid at the accelerator pump assy cheap at your local auto parts store simple you... Hesitation disappears replace fuel filters and overhaul the carburetor is a lean stumble from the regulator setting on Edelbrock! Leak somewhere usually a stumble like your describing is a Holley 750 with vacuum secondary i hold. Hokey Ass Message Board ' started by mohead1, Mar 10, 2013 idle due... Plate and phenolic.5 '' spacer slowly and smoothly push the accelerator pump.! Think i would benefit from the 0.28 '' that was in it an idle mixture screws in 1/8-1/4. Idle and idle mixture settings by incorrect fuel-to-air ratios result from the ''... The Thunder series has an adjustable air dam mounted above the idle mixture screw, the headers!