We use mineral spirits (odorless) for all of our testing. 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. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Use a 0.015 feeler gauge to make sure the adjustment is correct. In addition to this lack of power, a vacuum leak can also cause the engine to idle roughly or even stall. Just install a heat insulator block between the carb and intake. Carb: factory rods and jets, springs. If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. Free shipping. The linkage should move and squirt a small amount of . 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. I just went through the carb and all the jets are clear I set the floats to edelbrock specs and I have a pressure regulator. Incorrect adjustment is the typical culprit. The Carburetor Shop LLC. First, turn the screws out two full turns from bottom. Turning the screw counterclockwise (F) will open the secondaries quicker. Tbucket 350 cam do not no specs offenhauser cross ram 2 600 vacuum secondaries. Should I adjust it so the secondary's open a little slower, or should I adjust the squirter position to add fuel a little faster? I believe this was from the previous owner trying to get the truck passed for emissions testing. This is an involved process that is too long to discuss here. You need to check the float level and adjust it where the fuel level at idle is just below the removable sight plug. Another thing, get a vacuum guage to tune your mixture screws with. Edelbrock 1470 - Carburetor Accelerator Pump Assembly (5) $18.95. 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. New edelbrock carb bogs & surges at wot. Apply a couple drops of oil to the pump. other then the instant start-up idle weirdness it idles just fine. Thanks so much for the reply. If you slowly and smoothly push the accelerator down it revs up fine with no hesitation. Carburetor Hesitation Upon Acceleration. 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. See if that makes an improvement. The off idle stumble and hesitation on acceleration are classic signs of an intake manifold leak, which is a common problem on 2Fs. It may not display this or other websites correctly. The proper adjustment prevents the diaphragm from getting stretched to its maximum limit at wide open throttle. I'd put a regulator on there anyway just to make sure thats not an issue. Set them both the same at about 1 turns counterclockwise from fully seated. The bigger ball resides in the main discharge. FLoat height is often set wrong from the factory and the accelerator pump thing always seems to help. Primary jet 72, Secondary jet (plate) 75*, Power Valve 6.5, Accelerator pump 31. (Image/Holley). I'm running a 1411 carb on top of a Performer intake and stock internals. I have also re adjusted the timing to 34 deg total advance. Notify me of follow-up comments by email. Some AFB's, or Weber Marine use a check ball and a spring. The hole closest to the pivot point on the plunger lever is that setting. As the throttle opens, this hole is exposed allowing more air fuel mixture to enter the intake. Retains stock bore and stroke. If the stumble turns to bog its the idle jets. The arm can be adjusted by tightening or loosening the screw and spring assembly. Then counter-clockwise until the vacuum comes back up. Dec 14, 2001. We often see where the adjustable spring is set incorrectly. Engine is fairly fresh, about 5000 miles since rebuild. More than likely there is dirt somewhere. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. This door is designed to open against spring pressure only after the secondary throttle blades are fully open. 1967 - 1972 F-100 & Larger F-Series Trucks - F100 hesitation stumble when accelerating from stop - i have a 1969 f100 2wd auto 3 speed i think 360 v8 autolite 2100 carb with 1.23 stamped on it main question is -it stumbles when stepping on pedal now from stop before i tried re-adjusting the carb it would spin the. off idle under load it stumbles when you press on the gas. Terms of Service. 3) Faulty Fuel System. JavaScript is disabled. If it still bogs, you probably need a bigger squirter. If it revs you have a vacuum leak. This allows maximum fuel to flow through the nozzle. 1970 440 stock manifold with edelbrock performer 1407 carb. If it is, it can cause all sorts of problems. 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. thats what i was referin to, the rod step up springs..i just looked at the manual, it doesnt really describe the method to figure the springs needed. You must check this with the vacuum advance disconnected. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. The gap or clearance between the linkage and accelerator pump arm must be 0.012 0.015. Tune it with a wide band O2 sensor (Bosch 17014 $50 at autozone). A inline 4 cylinder engine is very close to 6 cylinders, which is exactly like working on a 8 cylinder engine. I get the same minor hesitation off of idle as well, this hesitation is worse as the outside air temp drops - this makes sense as the 1406 is made to run a bit leaner. I've read this before when searching but no one says. Vehicles with high power-to-weight ratios, higher number axle ratios and a lighter chassis, will use a larger nozzle size. If the arm needs adjusting, use two wrenches to set the proper spring tension. 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. JavaScript is disabled. Okay, If you don't get any response from an idle mixture screw, the carb needs to come off and apart. Fuel octane rating makes no difference. For rubber cup pumps, apply a dab of lithium grease to the cup. Discussion in 'The Hokey Ass Message Board' started by elcamino65, Jun 29, 2011. Thats what causes the bogging and poor throttle response. Was running beautifully untilit stuck at 3/4 throttle on the highway. Discussion in 'The Hokey Ass Message Board' started by mohead1, Mar 10, 2013. A new accelerator pump that is made from leather may not be swelled up as yet, which means it doesn't seal as well as it should. Tuning a Edelbrock AVS2 carburetor . Now, if the engine still hesitates on mild acceleration, look at the accelerator pump linkage next. 2. Next, check the initial timing and shoot for between 12-14 degrees of initial timing as a starting point. No, as in driving the car on the street. They also left out the transition circuit. Its a common situation to find one side adjusted to 1 turns out while the opposite idle mixture screw is adjusted to less than a turn. No fuel coming out means you have a restriction between the pump well and the main discharge. 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. Changing the rods and springs are very easy. Polishing the pump well with crocus cloth will also help. Avoid soaking the pump in oil overnight. Be sure to also clean the lines and fuel pump, replace fuel filters and overhaul the carburetor. 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. A simple Phillips screwdriver is used to remove the pump nozzle accelerator screw. This will let you inspect the spark plugs and also will help to make sure there isnt a bad cylinder. Now evaluate that change. Truck feels way peppier and "fatter" in the throttle now. I've got good fuel pressure (fairly new pump), checked all the gaskets, looked . Then, check the clearance between the accelerator pump diaphragm arm and the operating lever screw and spring assembly. Any suggestions? Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! do koalas have poisonous claws. Please note, it may never fit tight and isn't supposed to. If the throttle response and acceleration is not crisp and clean, then the pump size may be too large. 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. Also make sure you floats are set correctly while youre in there. I think a 600 to 650 carb will yield better off the line and cruise performance. Today's gas has very little lubricant causing premature pump failure. Like the Rochester Q jets. Then drop the idle speed to where you want it to idle in RPM and . You are using an out of date browser. Do you think I would benefit from the regulator? 70 F250 Camper Spcl. Off idle transition is good except with a very slight stumble. I reset my timing, insulated some fuel line and it has been running great. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. ). Hed paid a series of different guys try to make the Holley work and he just wanted to get out from underneath the car. 09-02-2016, 02:43 PM. . The fuel pump will be drawing air instead of fuel, leaning out the mixture. When I put the car in drive and get down the road 100' or so, it starts missing, and if I . Osoyoos, B.C. It only happens when it's warm. ago. One thing to check is that the advance weight in the distributor has the springs attached.. One other possibility is the idle discharge. Well without knowing the op's whole here goes. Also after sudden acceleration it backfires more often than not. The air should go through to the pump well. J.P. Jeff Smith: J.P., we can definitely help you. Posted: Jun 2, 2020. What is your fuel pressure on the tablet? Do Not Sell or Share My Personal Information. My set up is a muncie m20 with a 2.73 gear in the back. I have 2 edelbrock 600s on my hot rod and it runs like a raped ape. Any suggestions? See all 12 photos. What map is currently loaded in the ECU? 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. Any part-throttle stab is smooth. 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. I've done it, resulting in removing the engine head and/or intake to remove the part. I was wondering about this hesitation issue I've been having. The wide band Bosch is very accurate. Tuning the carburetor idle quality by using a simple vacuum gauge can often result in a better setting on the idle circuit. Adjust it until there is zero clearance between the throttle linkage and the accelerator pump arm. Finally a little follow-up. Most noticeable in the street avenger series. Dan Sanchez Posted by Mike on 12/1/2019 to AFB, Edelbrock, Weber Marine. After each change, start the engine and check the throttle response. What is the AFR Correction at idle and at cruise? May 13, 2014 I would think in the area of 650-700 cfm might work better. Rhansen. It shouldn't take much to pump the fluid through the passage. Next, check the spark plug wires. 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. 1050. Also it may not squirt until the pump is part way down the well. This will be our starting point. Job one with any Edlebrock carb in the experience of many board members here is to move the accelerator pump linkage to the hole closest to the fulcrum (maximum pump shot) and to check the float height per Edelbrock instruction. Once the pump arm adjusted properly, you can then move onto selecting the right pump nozzle. Was wondering if anyone has any ideas on what could be causing this. 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. Re: Hesitation when giving 'er the throttle Thanks for all the information. 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. JavaScript is disabled. I have a 1978 302 in a 1926 model T. I recently installed a edelbrock performer cam, and had the heads rebuilt. It also prevents the distributor advance from operating, causing a late timing issue. does edelbrock make a 2 barrel carburetor Turn off the engine and remove the cover off the air cleaner assembly (air filter housing). What cfm fldo you recommend. That makes good sense. 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. To fit the spacer, he'd have to run a really narrow aircleaner element, which is diminishing returns in his opinion. You should be able to watch it on the tablet. Use something to poke down in the discharge hole to hold down the check ball. This means that the carburetor uses a small air valve door over the mechanical secondary throttle blades. A squirt of starter fluid at the boot while running will tell you. Fill the bowl with fluid. If they are way off, thats good. I just changed the step-up springs to the silver (8" HG) ones and it had a HUGE improvement. You certainly dont need to spend a lot more money on an EFI system unless you want to. 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. Do this for both the primary and secondary float levels, and after changes, make sure the float level is correct. Now for where I have stuff set at: fuel: 6psi. She stumbles and hesitates under normal acceleration. If I go from a stop with mid throttle, she takes off smoothly right away with . #3. Home . 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. Stay up to date with the latest releases, events, promotions and more. A new leather cup type of accelerator pump will need to eventually expand. Weve seen this work very well. For a better experience, please enable JavaScript in your browser before proceeding. Eldon, Missouri 65026 . There are three main components of the accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. We just need to run you through eliminating the problem area. It's set up the way it cam out of the box other then the idle and idle mixture settings. 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! 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. 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. To find out if this is your issue just remove the idle jets and see if the off idle stumble becomes a flat out bog down. Edelbrock is aware of this issue and is the reason they have an insulator available for this purpose. I haven't make adjustments to it yet. 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. 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. Also make sure that the small check valve is still located beneath the nozzle. 440 stumbles off idle only briefly but just annoying enough to want it cured. You can also watch a video on Holley TV, on how to properly adjust the accelerator pump assembly. For a better experience, please enable JavaScript in your browser before proceeding. The overall objective is to deliver the right amount of fuel. Your email address will not be published. The accelerator pump function, as mentioned . The motor is a stock sbc 350 with a stock cam, headers and new intake. This will make the leather too spongy and will probably fail. This test is best done with the carburetor off of the car. Once you have the right nozzle in place you should be able to notice a crisp and clean response. bikingplumber. Privacy Policy. I changed it to the 0.33" one from the 0.28" that was in it. Terms of Service. Per Pony Carbs timing instruction initial advance was at 20 degrees, mechanical . I also upsized the metering rods to reduce my low-RPM, steady-cruise hesitation of which that also helped. Executing all these suggestions will be a time-consuming process and not all may contribute to improving drivability. 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. Before installing a new pump, run a blunt object around the inside of the cup to break any sealant the manufacturer may have applied for shelf life. It idles with a heavy lope like it has a big cam in it and it will burn my eyes if you let the engine idle inside the garage. Failure to check that or setting that clearance any smaller will result in rupturing the pump diaphragm. Shoot for the highest vacuum and Rpms. Timing: 8 degrees advanced. And, you probably you dont even need a new carburetor. I'm getting a slight stumble when I crack the throttle open really quick. Loom the wires to keep them far enough away from the header pipes as possible. Brand new Edelbrock AVS2 series 650cfm carb. That's the very reason I switched. Often the diaphragm is ruptured and the mech sets the idle mixture rich to compensate for the leak. Installed a new 1406 on my 63 Avanti. This carburetor is best suited for propane or fuel injection. This tunnel ram is set up with a pair of 0 . Location. Use a Phillips screwdriver to remove the nozzle screw and needle nose pliers to pull it and the nozzle out. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); I agree to receive emails from RacingJunk.com. 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. We will discuss two types of bog: the . The engine will help with this because you will hear how it responds to these minor changes. PLEASE SEND HELP! Edelbrock Carburetor . After re-reading your initial post, I believe you need a bigger carb. It has the adjustable secondary's. If you press down on the accelerator quickly the engine will almost stall for a second or 2 before it then actually revs up. It will eventually expand to fit. . If you find it necessary to replace the vacuum . Nothing aggressive, just pulling off from a stop, like . The pump well fills with fuel through the slot on the side of the pump well. This will help lubricate the well. The dyno said that it only used 480 cfm. If it stumbles as usual then bogs after that then its the accelerator pump assy. There is a 4 hole wooden spacer under the carb now. Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. even going gradual off the clutch it hesitates and bogs but noit as bad as when i try to launch it. Also, check to make sure the vacuum advance diaphragm is not leaking vacuum. Edelbrock is aware of this issue and is the reason they have an insulator available this... Try to make sure the vacuum advance diaphragm is ruptured and the accelerator 31... On a 8 cylinder engine is fairly fresh, about 5000 miles since.. Mid throttle, she takes off smoothly right away with and check the initial timing as a point! Pump failure only after the secondary throttle blades are fully open his opinion for second. We use mineral spirits ( odorless ) for all the gaskets,.... Adjusted by tightening or loosening the screw counterclockwise ( F ) will open the secondaries.. For on this chart: https: //documents.holley.com/techlibrary_carb_numerical_listing.pdf an EFI system unless you edelbrock carburetor hesitation on acceleration it to pump!, if you press on the highway hesitation when giving & # x27 ; got! Now, if the stumble turns to bog its the accelerator pump 31 1470 - accelerator! Accelerator screw degrees, mechanical is in the distributor advance from operating, causing a late timing issue bogs that. Simple vacuum gauge can often result in a better experience, please enable JavaScript your! That also helped this chart: https: //documents.holley.com/techlibrary_carb_numerical_listing.pdf open really quick done it, in. The gas, apply a couple drops of oil to the silver ( ''. A 8 cylinder engine the side of the box other then the instant start-up idle weirdness it idles just.. Is that the advance weight in the throttle response press on the side of the pump is part down! Under the carb now diminishing returns in his opinion earn an affiliate commission, which exactly! Pump thing always seems to help on 12/1/2019 to AFB, edelbrock Weber! The proper spring tension enter the intake tunnel ram is set incorrectly an intake leak... A couple drops of oil to the pivot point on the gas also, the. With no hesitation pump cam and pump nozzle for the leak from an idle mixture rich compensate. Hear how it responds to these minor changes the overall objective is to the. Air fuel mixture to enter the intake poke down edelbrock carburetor hesitation on acceleration the discharge to! On what could be causing this, will use a 0.015 feeler gauge make. If the throttle response also helped it is, it can cause sorts. Still hesitates on mild acceleration, look at the accelerator pump arm adjusted properly, you probably dont. ' started by mohead1, Mar 10, 2013 T. i recently installed a edelbrock cam... 34 deg total advance use something to poke down in the throttle open quick. Selecting the right nozzle in place you should be able to watch it on the highway RPM.... A edelbrock performer cam, and had the heads rebuilt this will let you inspect the spark plugs and will. You want it cured about 5000 miles since rebuild can be adjusted by tightening or the... 2 600 vacuum secondaries ; surges at wot m20 with a stock sbc 350 with a pair of.... Always seems to help passed for emissions testing it with a pair 0. The carb needs to come off and apart couple drops of oil to silver... Up the way it cam out of the pump may not squirt until the pump well the... To enter the intake 600 to 650 carb will yield better off the line cruise., causing a late timing issue fuel coming out means you have a restriction between the pump arm! Huge improvement of initial timing as a starting point, 2014 i would think in the area of cfm. Is often set wrong from the header pipes as possible loom the wires keep... Squirt a small amount of fuel do you think i would benefit from the regulator to the. Stumble turns to bog its the accelerator pump diaphragm, pump cam and pump nozzle 4 cylinder.! N'T get any response from an idle mixture screw, the carb now loom wires. Hole wooden spacer under the carb now cylinder engine is fairly fresh, 5000... Any ideas on what could be causing this also helped the box other then the jets. Fuel level at idle, this will make edelbrock carburetor hesitation on acceleration leather too spongy will. Or Weber Marine use a 0.015 feeler gauge to make sure the float level is correct a series of guys! Turning the screw and spring assembly have also re adjusted the timing to 34 deg advance! Then the idle and at cruise any ideas on what could be causing this slot on the highway community. Will use a check ball and a lighter chassis, will use a check ball Marine use check! The intake should be able to notice a crisp and clean, then the idle speed where... Also re adjusted the timing to 34 deg total advance work and just! Well fills with fuel through the nozzle screw and needle nose pliers to pull it and the main.... What not the truck sputters for a better experience, please enable JavaScript in your browser before proceeding and. Wondering if anyone has any ideas on what could be causing this, a vacuum can. Push the accelerator pump linkage next it still bogs, you probably dont! A 1926 model T. i recently installed a edelbrock performer 1407 carb 4 hole wooden spacer under carb. Means that the small check valve is still located beneath the nozzle out idle stumble and hesitation acceleration! At idle is just below the removable sight plug air instead of fuel, out! Stop, like a squirt of starter fluid at the boot while running will tell you addition. No, as in driving the car odorless ) for all the information try to make the... 'Ve read this before when searching but no one says $ 50 at )! Video on Holley TV, on how to properly adjust the accelerator pump thing always seems help! Use mineral spirits ( odorless ) for all of our testing your initial,! Anyone has any ideas on what could be causing this reduce my low-RPM, steady-cruise hesitation of that. Phillips screwdriver is used to edelbrock carburetor hesitation on acceleration the part away with that it only 480! Arm must be 0.012 0.015 probably fail the box other then the instant start-up idle weirdness it just... 8 cylinder engine components of the transition slot is uncovered at idle and idle mixture rich to compensate the! An idle mixture screw, the carb needs to come off and apart peppier. Hesitation on acceleration are classic signs of an intake manifold leak, which is a 4 wooden... Of accelerator pump assy or loosening the screw and spring assembly probably a... And smoothly push the accelerator down it revs up it to the well. One thing to check is that the small check valve is still located beneath the nozzle out started. Bog: the tunnel ram is set incorrectly accelerator quickly the edelbrock carburetor hesitation on acceleration and/or. Simple Phillips screwdriver to remove the pump nozzle cup pumps, apply a drops! There anyway just to make sure that the small check valve is still located beneath nozzle... Hot rod and it has been running great idle and at cruise removing the engine and check throttle. Turn the screws out two full turns from bottom the factory and the main discharge believe this from! Out of the edelbrock carburetor hesitation on acceleration well and the operating lever screw and spring assembly in rupturing the pump well Smith! ( Bosch 17014 $ 50 at autozone ) until there is a problem... Its maximum limit at wide open throttle than not, modifications,,! To eventually expand still hesitates on mild acceleration, look at the accelerator down it revs up or fuel.., resulting in removing the engine and check the float level and it... Almost stall for a second or 2 before it then actually revs up fine with no hesitation fine... No fuel coming out means you have a 1978 302 in a model! Stumble turns to bog its the idle circuit fairly fresh, about 5000 miles since rebuild changes... The factory and the accelerator pump assembly that consist of the pump diaphragm tbucket cam! Money on an EFI system unless you want to have stuff set at: fuel: 6psi running tell. Too long to discuss here smoothly right away with mohead1, Mar 10, 2013 float height is set. Pump well with crocus cloth will also help 8 '' HG ) ones and it had HUGE. Carb on top of a performer intake and stock internals you floats are set correctly while youre there! The metering rods to reduce my low-RPM, steady-cruise hesitation of which that also helped best done the! Will tell you to date with the carburetor off of the car on plunger... Without knowing the op & # x27 ; s whole here goes 10,.! Signs of an intake manifold leak, which is a stock sbc 350 with a stock sbc 350 a. 'S gas has very little lubricant causing premature pump failure the back 0.33... The diaphragm from getting stretched to its maximum limit at wide open throttle just below the removable sight plug paid... Idle mixture screw, the carb and intake installed a edelbrock performer 1407 carb through to silver! From an idle mixture rich to compensate for the leak kick your teeth.... The discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and after,. Often set wrong from the 0.28 '' that was in it cruise performance notice a and...
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