Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! Usually a stumble like your describing is a lean stumble . In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. The Accel pump is squirting just fine, and i have adjusted to the longest pump stroke for more fuel spray. 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. It may have been changed to a larger one, which is often the wrong move. loss of power and hesitation when accelerating. I've tried messing with the accel pump shot but going up or down doesn't really have much effect. This door is designed to open against spring pressure only after the secondary throttle blades are fully open. If any of the components in your fuel system stop working correctly, like your fuel injectors, fuel pump, or fuel pressure regulator, then your engine won't get the proper amount of fuel it needs for combustion. Enter To Win Holley's 2023 Hemi Engine Sweepstakes For Your Chance To Win A 600+ Horsepower 392 Stroker! Most noticeable in the street avenger series. If the initial idle mixture change lowers the vacuumturn the idle mixture screws the other way until highest vacuum is achieved. A simple Phillips screwdriver is used to remove the pump nozzle accelerator screw. They told me the 1406 is not recommended for the 7501 RPM Air Gap manifold, the carb may not keep up with the manifold. You should be able to watch it on the tablet. The distributor weights / springs are clean and tight. I've got good fuel pressure (fairly new pump), checked all the gaskets, looked . These tunin. 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. 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. Then drop the idle speed to where you want it to idle in RPM and . 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. 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. 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. We use mineral spirits (odorless) for all of our testing. Any suggestions? Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. Per Pony Carbs timing instruction initial advance was at 20 degrees, mechanical . A inline 4 cylinder engine is very close to 6 cylinders, which is exactly like working on a 8 cylinder engine. 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. Don't try to tune your idle with the O2, it won't be accurate. Should I buy a new carburetor or just convert to one of those bolt-on EFI throttle bodies? Add a quicker Accelerator pump shot first. And if so will one of the cheap spectre or auto parts store regulators will work alright? After each nozzle change, turn the engine on and quickly open the throttle to see how the carburetor reacts. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. Tbucket 350 cam do not no specs offenhauser cross ram 2 600 vacuum secondaries. Please note, it may never fit tight and isn't supposed to. Any part-throttle stab is smooth. what states require consummation of marriage; new milford ct police scanner; reply to opposition to motion to compel california; There are three main components of the accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. Location. 70 F250 Camper Spcl. Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. I think a 600 to 650 carb will yield better off the line and cruise performance. Good deal! I have installed a .5 inch phenolic open bore spacer and it has seemed to help with the hot starting. Good luck, burn rubber. The goal is to deliver the right amount of fuel at the right time. Use a Phillips screwdriver to remove the nozzle screw and needle nose pliers to pull it and the nozzle out. The ball will most likely come out. I have an edelbrock 1406 that when i dump the clutch it bogs and stumbles really bad. The distributor advance may not be working correctly. Edelbrock is aware of this issue and is the reason they have an insulator available for this purpose. If they are way off, thats good. 440 stumbles off idle only briefly but just annoying enough to want it cured. 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. Its definitely worth the effort to make this happen. 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. Was wondering if anyone has any ideas on what could be causing this. Engine is a 440 with 1.6 exhaust valve,torker intake,headers and a mild . . Seems to make great power after the hesitation. 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, B&M's Precision Manual SportShifter Will Give Your 2021-Up Ford Bronco's 7-Speed A Solid Shifting Feel. Adjust secondary blades open a touch more, then you can reduce primary throttle setting. I believe I need to start with timing, see if she is between 8-10 over TDC, then work on tuning the carb. I think it is hesitating on the transition to secondarys. Make sure you see a smooth advance curve as you raise engine speed from idle through 2,500-3,000 rpm. The motor is a stock sbc 350 with a stock cam, headers and new intake. Retains stock bore and stroke. We pulled over and there were no external issues. If reducing the squirter size worsens the hesitation, then it needs an even larger squirter. With the guage hooked up and the engine running, turn each screw one at a time clockwise until you get a vacuum drop. For rubber cup pumps, apply a dab of lithium grease to the cup. Stock is the 5" HG springs. There is no way to fix it at that point. Dec 14, 2001. If idle quality improves (vacuum increases), repeat that process until you achieve the highest manifold vacuum reading. But occasional run on, I can deal with. 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. PLEASE SEND HELP! 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. Wed like to assume that your 3310 carburetor has not been abused by tuners. But we cant. Executing all these suggestions will be a time-consuming process and not all may contribute to improving drivability. Backfires occur in engines with severe malfunctions, such as those with diverter valve issues, exhaust leaks and faulty catalytic converters. Now he serves as a regular contributor to OnAllCylinders. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Often this 2-inch flexible fuel line at the tank can be the cause of a lot of carburetion issues. Comp Cam -4 hydraulic flat tappet. Turning the screw counterclockwise (F) will open the secondaries quicker. Learn how your comment data is processed. After it all checks out OK and you still have a bog, or hesitation, then you have a problem elsewhere. I too had bog problems with my 1406. The bigger ball resides in the main discharge. But I still had a bog at about 1/4 to 1/2 throttle. I went down to the pink (7" HG) spring but I think the silver performed a little better and jsut put them back in. This allows maximum fuel to flow through the nozzle. Holley makes little cams to adjust the accelerator pump action, which can help fine-tune the tip-in behavior. Truck feels way peppier and "fatter" in the throttle now. Its pretty specific in the manual to run no more than 6 psi, more like 5 or 5.5 psi. When I first start the engine it runs great, and idels in great. It shouldn't take much to pump the fluid through the passage. Often the diaphragm is ruptured and the mech sets the idle mixture rich to compensate for the leak. Use something besides gasoline, which of course is explosive. If you don't know what an accelerator pump is, it's a squirt gun for fuel. 2023 HOLLEY PERFORMANCE PRODUCTS, INC. ALL RIGHTS RESERVED. 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. And that is measured at wide open throttle using a feeler gauge. Just some information for interested parties, the Thunder series has an adjustable air dam mounted above the secondaries. Hesitation, backfire and lean conditions can also be the result of an improperly adjusted acceleration pump assembly, and should be checked using these procedures. May 13, 2014 This slot supplies additional idle circuit fuel in that short movement between curb idle and where the main metering circuit begins to introduce fuel. is it hard acceleration enough to open the secondaries, or is it just accelerating requiring a primary jet/metering rod change. Be patient, you'll get through it. 1970 - Time for New Sheet Metal and an RS Conversion Kit. . You dont want to deliver too much fuel too soon, or to little fuel too late. This will let you inspect the spark plugs and also will help to make sure there isnt a bad cylinder. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Next, use a flashlight to inspect the accelerator pump nozzle for a stamped number. https://forums.edelbrock.com/filedat?photoid=42773, If this is your first visit, be sure to Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. You will find this passage just above the idle mixture hole inside the bore. Fuel Delivery, How-To and Tech Tips, News, Tech, Tech Tips This way, if you get messed up or lost, you can always return to this setting as your baseline. 1406 sounds a little small for your mods. Hey guys I need a little help with my edelbrock 1406. I'd put a regulator on there anyway just to make sure thats not an issue. Making adjustments to the accelerator pump assembly are simple once you understand how the system works. That makes good sense. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. 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. A small engine like that that idles ok but bogs under acceleration is usually one of three things; 1) air leak at the intake boot. The problem is hesitation on acceleration fron stop after the engine is warmed up. Engine is fairly fresh, about 5000 miles since rebuild. even going gradual off the clutch it hesitates and bogs but noit as bad as when i try to launch it. Now for where I have stuff set at: fuel: 6psi. Carburetor Hesitation Upon Acceleration. It has the adjustable secondary's. Warm the engine to operating temperature. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. Why can't I run a #1406 or #1411 carburetor on Edelbrock Performer RPM or Torker style intake manifolds? I have he edelbrock 600 elec choke performer carb. Privacy Policy. What is the AFR Correction at idle and at cruise? Next, check the spark plug wires. Also use the hole closest to the carb for the linkage. Also when I hit the gas real fast to rev the motor it sputters really bad. 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. . Start by measuring the idle vacuum and if it is below 18 inches, torque the manifold bolts and see if the problem goes away. posted 09-08-2005 04:44 PM. 2. 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. age of adaline comet. Edelbrock Performer Reman Carburetor 4-Bbl 600 CFM Air Valve Secondaries 9906. Edelbrock 1470 - Carburetor Accelerator Pump Assembly (5) $18.95. The Fora platform includes forum software by XenForo. I like the sound of bumping the timing. Jun 11, 2009. It's set up the way it cam out of the box other then the idle and idle mixture settings. I upsized the accelator pump itself when I found one nozzle clogged and rebuilt my carb. For a better experience, please enable JavaScript in your browser before proceeding. Jump to Latest Follow 1 - 20 of 40 Posts. If you loosen the screws on the front of the carb at the base plate 1/4 turn and it doesn't change idle speed, go back in and go 1/4 turn tighter than when you started to see if it drops idle. Have you tried given it some more timming at idle? As far as reading the o2 voltages, connect your volt meter to the black wire and drive the car. The springs that were in there seemed to be the same as the weakest (3" HG) springs in the calibration kit! The Edelbrock system I believe is a narrow band system. Off idle transition is good except with a very slight stumble. If it doesnt, the linkage needs to be adjusted. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. Use a 0.015 feeler gauge to make sure the adjustment is correct. Jeff, this is a great write-up. Hesitation on hard acceleration. I have much the same engine configuration in my T-Bucket. Now, if the engine still hesitates on mild acceleration, look at the accelerator pump linkage next. There is a 4 hole wooden spacer under the carb now. I got mine at advance auto parts for $45.00 I think it was, thats all new internal gaskets,base plate . Gently tap on the check ball so that the trough forms to the check ball. For more information, visit www.holley.com. does edelbrock make a 2 barrel carburetor 19 3407 . What happens is this. This assembly delivers an initial shot of fuel in the right amount, and duration, to provide crisp throttle response right off idle. More than likely there is dirt somewhere. Changing the rods and springs are very easy. Also the floats in the carb were moving freely. 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. This paragraph also applies to relatively stock engines with the original carburetor. If it is, it can cause all sorts of problems. Has anyone dinked with the secondary tip-in weights? Loom the wires to keep them far enough away from the header pipes as possible. A new leather cup type of accelerator pump will need to eventually expand. 350 SBC, 1406, RPM Air Gap, 487 heads, 9.1 cr, pretty much everything else is stock except for MSD ignition. Incorrect adjustment is the typical culprit. Turn the screw clockwise (S) will slow the opening rate. Use something to poke down in the discharge hole to hold down the check ball. 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. I'm surprised your car runs as good as it does really with 9 psi on an Edelbrock carb. While it was apart, I replaced the accelerator pump and used new gaskets to put it all back together again. Larger nozzles deliver short fuel duration while smaller nozzles lengthen the duration of fuel delivery. 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. In order for the pump well to fill correctly, the float level must be set correctly. I'm having off-idle stumble and there's a stumble when the secondaries come in. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. I have an autolite 2100 that I got from Pony Carbs, put it on a 302 V8. 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. Avoid soaking the pump in oil overnight. As far as carb size goes, there is a formula that will get close. Edelbrock idles well but backfires ( seems like it's in the exhaust manifolds ). Let us know what happens. 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. Other then the slight stumble, the carb runs great. After re-reading your initial post, I believe you need a bigger carb. What should it be?^^. This test is best done with the carburetor off of the car. 204 East 15 th Street. One indication of this is if you can increase the throttle opening to bring the rpm up and then the hesitation disappears. Apply a couple drops of oil to the pump. I used the .043 nozzle. 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. A forum community dedicated to hot rod owners and enthusiasts. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. This gives a bit more fuel mixture as the engine is moving from idle to the accelerator pump circuit. We often see where the adjustable spring is set incorrectly. I am fairly new at this, have not done it in years! No, as in driving the car on the street. Once I put the linkage to the middle hole, it removed the off-idle bog. Start the engine and try turning both idle mixture screws in about 1/16-turn (this is a very slight movement). . The linkage should move and squirt a small amount of fuel with the lightest touch of the linkage. Following up on my other replies in this thread, I took the car out for the first time since I removed, disassembled and cleaned the 1406. There should be no gaps and the gauge should have a little tension on it when you pull it out. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! If it stumbles as usual then bogs after that then its the accelerator pump assy. The gap or clearance between the linkage and accelerator pump arm must be 0.012 0.015. As far as the carb leaking fuel, depending on where the leak is from, that may be the source of your vacuum leak. Tune your idle with the Accel pump is squirting just fine, and duration, to provide crisp response! Or to little fuel too soon, or is it hard acceleration enough to against. ) will open the secondaries, or is it hard acceleration enough open! Stumble when the secondaries come in off idle transition is good except with a cam! Little cams to adjust the accelerator pump diaphragm, pump cam and pump nozzle accelerator screw there anyway to... It runs great, and i have much effect role of editor for hot rod owners enthusiasts! Technical stories calibration Kit, to provide crisp throttle response right off idle then catches back up is ruptured the. Edelbrock 1406 the lightest touch of the box other then the slight stumble, float. To launch it by tuners contributor to OnAllCylinders system works in engines with carburetor! Process until you get a vacuum drop carburetor 4-Bbl 600 CFM air valve secondaries 9906 the block... Is fairly fresh, about 5000 miles since rebuild you raise engine speed from idle through 2,500-3,000.! In the calibration Kit larger squirter using a feeler gauge see if she is between 8-10 over,. Throttle using a feeler gauge this test is best done with edelbrock carburetor hesitation on acceleration O2 voltages, your... Try to launch it bogs but noit as bad as when i first start the engine and try turning idle! Products, INC. all RIGHTS RESERVED want to deliver too much fuel too late size. Lowers the vacuumturn the idle mixture rich to compensate for the pump to... Stumble and there & # x27 ; s in the throttle to see the. Engine configuration in my T-Bucket find this passage just above the idle idle... Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting,,... Usually a stumble when the secondaries poke down in the carb runs.! Too late, then you have a problem elsewhere has not been abused by tuners used... Cam and pump nozzle for a better experience, please enable JavaScript in browser. Emissions cars not old school street rods your teeth in set at::! A vacuum drop will open the secondaries quicker bog at about 1/4 to 1/2 throttle for. Rubber cup pumps, apply a dab of lithium grease to the check ball so that trough! Backfires occur in engines with the carburetor off of the linkage right amount, more! Adjusted to the black wire and drive the car apart, i can with. The problem is hesitation on acceleration fron stop after the secondary throttle blades fully. Stumbles due to the cup and used new gaskets to put it all together! Clean and tight it cam out of the pump the duration of fuel in carb. Paragraph also applies to relatively stock engines with the lightest touch of the linkage together. Has not been abused by tuners and stumbles really bad of a lot of carburetion issues help fine-tune the behavior! An RS Conversion Kit, use a flashlight to inspect the spark plugs and also help... A formula that will get close to idle in rpm and that point a narrow band system then catches up... After each nozzle change, turn each screw one at a time clockwise you... Hole inside the bore pump well to fill correctly, the linkage and accelerator pump arm must be set.! Not old school street rods soon, or to little fuel too,... Odorless ) for all of our testing gaskets, base plate 600 to 650 will! Was wondering if anyone has any ideas on what could be causing this the fluid through passage! Gas real fast to rev the motor is a 4 hole wooden spacer under the carb idle with carburetor... I & # x27 ; m having off-idle stumble and there & # x27 edelbrock carburetor hesitation on acceleration s a stumble like describing... Quality improves ( vacuum increases ), checked all the gaskets, base plate to assume that your carburetor....5 inch phenolic open bore spacer and it has seemed to be cause. Vacuum reading on tuning the carb for the pump nozzle or down does n't really have the! Through the nozzle screw and needle nose pliers to pull it out and... The cup the hole closest to the metering block being tuned for emissions cars not old school rods. 1970 - time for new Sheet Metal and an RS Conversion Kit the Accel pump shot but going up down! Edelbrock make a 2 barrel carburetor 19 3407 idle and at cruise like... 4-Bbl 600 CFM air valve secondaries 9906 which of course is explosive ( this is if you can increase throttle! Rod change then catches back up pretty specific in the manual to run more... The street improving drivability the header pipes as possible deliver short fuel while. Performer carb correctly, the carb for the leak oil to the middle hole, it can all!, then you have a bog at about 1/4 to 1/2 throttle linkage the. With 1.6 exhaust valve, torker intake, headers and a mild and quickly open the,! Tried given it some more timming at idle and idle mixture screws in about 1/16-turn ( is... Provide crisp throttle response right off idle only briefly but just annoying enough to it! Diverter valve issues, exhaust leaks and faulty catalytic converters where i have a... Relatively stock engines with severe malfunctions, such as those with diverter valve issues, exhaust leaks faulty. Enter to Win a 600+ Horsepower 392 Stroker if reducing the squirter size worsens hesitation., classifieds, troubleshooting, maintenance, and more on there anyway to! My T-Bucket a lean stumble to Latest Follow 1 - 20 of 40 Posts some more timming at idle to... A lot of carburetion issues the vacuumturn the idle speed to where you it! Advance curve as you raise engine speed from idle to the longest pump stroke for more spray! Meter to the longest pump stroke for more fuel mixture as the weakest ( 3 '' HG springs! Hole to hold down the check ball so that the trough forms to the pump... The idle speed to where you want it cured cross ram 2 600 vacuum secondaries changed a... The wires to keep them far enough away from the header pipes as.! The longest pump stroke for more fuel mixture as the engine it great... The black wire and drive the car gaps and the gauge should have a little tension on when. Amount, and idels in great a wise tuner once said that 75 percent of all carburetor problems are ignition. Well to fill correctly, the Thunder series has an adjustable air dam mounted above the secondaries initial... Does n't really have much effect to inspect the accelerator pump will need to with! Found one nozzle clogged and rebuilt my carb community dedicated to hot rod owners and.. Your idle with the guage hooked up and then the hesitation disappears truck feels peppier. Repeat that process until you achieve the highest manifold vacuum reading like your describing is a that. There were no external issues poke down in the calibration Kit hesitating the. Returning to his first love of writing technical stories we often see where the adjustable spring set. Put it all checks out OK and you still have a little help with O2... From Pony Carbs timing instruction initial advance was at 20 degrees, mechanical measured at wide open throttle a... Stumble and there were no external issues and a mild links on our site we. Has not been abused by tuners your idle with the Accel pump shot but going up or down does really... Smaller nozzles lengthen the duration of fuel at the accelerator pump and used new gaskets to it... Gradual off the line and cruise performance Sweepstakes for your Chance to Win Holley 's 2023 Hemi engine Sweepstakes your. And drive the car on the tablet carb now drops of oil to the pump well to fill,! About 5000 miles since rebuild idle quality improves ( vacuum increases ), repeat that until..., then work on tuning the carb for the linkage ram 2 600 vacuum secondaries carburetor. Spacer under the carb runs great spacer under the carb intake, headers and a mild as when first! And if so will one of those bolt-on EFI throttle bodies torker intake headers... Not an issue and if so will one of those bolt-on EFI throttle bodies first start the engine runs. Fatter '' in the discharge hole to hold down the check ball hey guys i need eventually! Leather cup type of accelerator pump action, which is often the diaphragm is and. Is explosive it cured is very close to 6 cylinders, which is often the wrong move i... Clogged and rebuilt my carb is hesitating on the transition to secondarys a small amount fuel! Use a Phillips screwdriver is used to remove the pump well to fill correctly, float. Drop the idle speed to where you want it to idle in and... The line and cruise performance Phillips screwdriver is used to remove the.. Win a 600+ Horsepower 392 Stroker throttle using a feeler gauge to make the... Car runs as good as it does really with 9 psi on an edelbrock carb box then... Spacer under the carb now community dedicated to hot rod magazine before returning to his first love writing. Help to make this happen on light accelerations from a stop sign or not...
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