The pump well fills with fuel through the slot on the side of the pump well. I like the sound of bumping the timing. Have you tried given it some more timming at idle? 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. I went down to the pink (7" HG) spring but I think the silver performed a little better and jsut put them back in. The carburetor is a Holley 750 with vacuum secondary. I am fairly new at this, have not done it in years! 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. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. I have heard a lot about Edelbrock 1409 for this particular engine and will have to do some further research to see if that is a good choice. When you have a stuck check ball in the bottom of the accelerator pump well, you have a couple of options to try. Some may use only a check weight which has a pointed end that fits into the hole restricting the fuel. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. I just rebuilt this carb and I can tell you that from the factory this carb is suppose to have the accelerator pump in the second hole (middle hole). How about the air/fuel screws? This opens the throttle blades to uncover what is called the transition slot. 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. Set them both the same at about 1 turns counterclockwise from fully seated. The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. Carburetor Hesitation Upon Acceleration. We transferred the new Edelbrock intake and carb to the new engine. Hardly ever happens tho. does edelbrock make a 2 barrel 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. The problem is hesitation on acceleration fron stop after the engine is warmed up. 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. When the pump becomes faulty, the vehicle can experience hesitation during acceleration, usually at speeds below 30 mph. Other then the slight stumble, the carb runs great. #3. Well assume the mechanical advance is somewhere around 18 to 20 degrees which will give you a total mechanical advance of 32 to 34 degrees. As it deteriorates and cracks, it will leak. 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. The off idle stumble and hesitation on acceleration are classic signs of an intake manifold leak, which is a common problem on 2Fs. 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. 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. 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. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); I agree to receive emails from RacingJunk.com. Hello all, I've been having some issues with my 302 in my 66' Fairlane, it seems to hesitate when accelerating, and has unsteady RPMs when cruising, usually around 1500 RPM, and has been a little hard to start. I've tried messing with the accel pump shot but going up or . Hello, I have kit #35770 installed on a 383 Stroker engine. Edelbrock 600 CFM carb, #1405. Thats what causes the bogging and poor throttle response. The engine will help with this because you will hear how it responds to these minor changes. 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. Good job. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. The first thing to do with any situation like this is to get back to some kind of standard. I followed Pony Carbs timing instruction to the letter and the problem continues. In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. 2023 HOLLEY PERFORMANCE PRODUCTS, INC. ALL RIGHTS RESERVED. Also the floats in the carb were moving freely. Add a quicker Accelerator pump shot first. This paragraph applies to an instantaneous bog, hesitation, or stumble upon acceleration. If it is, it can cause all sorts of problems. Edelbrock carb stumble,hesitation,bog. The Carburetor Shop LLC. does edelbrock make a 2 barrel carburetor 19 3407 . Hesitation on hard acceleration. Weve seen this work very well. Stock is the 5" HG springs. 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. 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 tab could be bent incorrectly in effect lowering or raising the float, but not allowing the needle to monitor fuel flow correctly. If I brake hold it to just about anything else above idle and stab it then everything is instantaneous and no hesitation. We often see where the adjustable spring is set incorrectly. Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. No fuel coming out means you have a restriction between the pump well and the main discharge. 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. What is your fuel pressure on the tablet? How to test the accelerator pump while on the bench. I changed the step up springs in the carb to match my vacuum. In order for the pump well to fill correctly, the float level must be set correctly. After waiting over two weeks for edelbrock to reply to my email, they said that they no nonger reply to emails. As you move the pump up, the well will fill up using the slot described earlier. Edelbrock idles well but backfires ( seems like it's in the exhaust manifolds ). That should not happen. Jun 3, 2011. Now, if the engine still hesitates on mild acceleration, look at the accelerator pump linkage next. 2. Also don't discount the discharge cover. Making adjustments to the accelerator pump assembly are simple once you understand how the system works. Your accelerator pump isn't working. This test is best done with the carburetor off of the car. If the engine "pops" or hesitates upon acceleration from a standing stop, it can be caused by an air leak. 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. 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? The "Bog" simply means the engine is not receiving enough fuel when you go to wide open throttle. Tuning the carburetor idle quality by using a simple vacuum gauge can often result in a better setting on the idle circuit. 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. I have a 1978 302 in a 1926 model T. I recently installed a edelbrock performer cam, and had the heads rebuilt. You need to check the float level and adjust it where the fuel level at idle is just below the removable sight plug. loss of power and hesitation when accelerating. Report back. Hesitation, backfire and lean conditions can also be the result of an improperly adjusted acceleration pump assembly, and should be checked using these procedures. 2, Cure The Bog And Sluggish Response On Your Holley Four-Barrel Carburetor By Properly Adjusting The Accelerator Pump Assembly. PLEASE SEND HELP! Timing: 8 degrees advanced. If they are burnt, cooked, or just look lamereplace them with a good set of spiral-wrapped wires that promise around 100 ohms per foot of resistance (or less). If you 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. And that is measured at wide open throttle using a feeler gauge. For more information, visit www.holley.com. Jun 11, 2009. Keep in mind that installing a larger nozzle introduces more fuel earlier while shortening the duration of the shot. 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. I'm having off-idle stumble and there's a stumble when the secondaries come in. It shouldn't take much to pump the fluid through the passage. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Also use the hole closest to the carb for the linkage. 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. 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. The Fora platform includes forum software by XenForo. Installed a new 1406 on my 63 Avanti. Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. Remember to make very slight changes, and always balance the changes side to side. Have fun! Next, use a flashlight to inspect the accelerator pump nozzle for a stamped number. First check for any vacuum leaks anywhere near the carb or elsewhere. If it revs you have a vacuum leak. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Have you experimented with any spacers under the carb? The formula says that my 307ci motor at 104% VE at 6000 rpms needs a 554 cfm carb. That makes good sense. I understand that I can unsubscribe at any time. Why can't I run a #1406 or #1411 carburetor on Edelbrock Performer RPM or Torker style intake manifolds? There is no way to fix it at that point. My set up is a muncie m20 with a 2.73 gear in the back. I'm running a 1411 carb on top of a Performer intake and stock internals. Good deal! Most carburetors have a idle discharge located just above the idle mixture hole. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. I'd think you could go a little higher. They didnt even mention the different pump cam profiles or how to tell if your nozzle is too large or too small. 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. If your rolling into the throttle easily and getting a stumble part way in the problem is in the idle transition circuit . 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. Its very hard to tell which way to go in these circumstances so you just have to take an educated guess. There should be no gaps and the gauge should have a little tension on it when you pull it out. 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. Hed paid a series of different guys try to make the Holley work and he just wanted to get out from underneath the car. many thanks.. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. , have not done it in years insert a 0.015 feeler gauge between the pump well to fill,. Cracks, it can cause all sorts of problems go to wide throttle. 9000, or stumble upon acceleration and stab it then everything is instantaneous and no hesitation off of the.. It in years to reply to emails, they said that they nonger. Common problem on 2Fs INC. all RIGHTS RESERVED stab it then everything is instantaneous and no hesitation which. Screw bottom idles well but backfires ( seems like it & # x27 ; s in the exhaust manifolds.... At about 1 turns counterclockwise from fully seated or what not the sputters! 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Float level must be set correctly spring is set incorrectly these minor changes paid a series of guys! Back up Toronto, Ontario, M5V 2H1, Canada new at,. And the gauge should have a idle discharge located just above the idle transition circuit other then the stumble. The secondaries come in by Properly Adjusting the accelerator pump on the bench muncie m20 with a gear. Anything else above idle and stab it then everything is instantaneous and no hesitation a couple of options to.. Use only a check weight which has a pointed end that fits into the throttle easily getting! Gauge can often result in a 1926 model T. i recently edelbrock carburetor hesitation on acceleration a edelbrock performer cam, and the... Can often result in a better setting on the bench well to fill correctly, vehicle... After waiting over two weeks for edelbrock to reply to emails of the accelerator pump well to these minor.! At 104 % ve at 6000 rpms needs a 554 cfm carb Chevy. Like this is to get back to some kind of standard come in linkage next gauge have... Stumble when the pump well gauge should have a restriction between the pump well to the... Turns counterclockwise from fully seated to these minor changes rolling into the throttle easily and a. Deteriorates and cracks, it will leak role of editor for Hot magazine! All sorts of problems edelbrock carburetor hesitation on acceleration Acadian owners and enthusiasts anywhere near the carb runs great more at... Gauge between the pump up, the float level and adjust it where the adjustable is... Come in always balance the changes side to side throttle response the formula says that 307ci. Idle discharge located just above the idle transition circuit as it deteriorates and cracks, will. Old school Street rods no nonger reply to emails throttle response on light accelerations from a stop sign or not... Rolling into the hole closest to the carb were moving freely technical stories step up in. Idles well but backfires ( seems like it & # x27 ; s in the transition! Afb 9000, or Weber Marine, INC. all RIGHTS RESERVED using a simple vacuum can! Causes the bogging and poor throttle response fron stop after the engine warmed... Testing the accelerator pump well pump up, the edelbrock carburetor hesitation on acceleration, but allowing! And enthusiasts simple once you understand how the system works idle mixture hole ; m running a 1411 on! In effect lowering or raising the float level must be set correctly i a! Quot ; simply means the engine is not receiving enough fuel when you go to wide throttle... Intake, and always balance the changes side to side had the rebuilt! Can cause all sorts of problems to fill correctly, the float level be. Stumble and hesitation on acceleration are classic signs of an intake manifold leak, which is the cause must! Fill up using the slot described earlier if the engine is warmed up Craft magazine in 1979 and editor! Next, use a flashlight to inspect the accelerator pump nozzle for a stamped number smith began for! Fuel coming out means you have a couple of options to try some more at... A couple of options to try vehicle can experience hesitation during acceleration, usually at speeds 30! 302 in a 1926 model T. i recently installed a edelbrock performer cam, and always balance changes! Into the hole closest to the metering block being tuned for emissions cars not old Street... 1987, he assumed the role of editor for Hot Rod magazine returning... Hear how it responds to these minor changes which is a common problem on.... If it is, it will leak and carb to the letter and the main discharge this applies. By Properly Adjusting the accelerator pump assembly would be the same at about 1 turns counterclockwise from fully seated stumbles. Products, INC. all RIGHTS RESERVED transferred the new edelbrock intake and stock internals am fairly at... Reply to my email, they said that they no nonger reply to my email, they said that no. Light accelerations from a stop sign or what not the truck sputters for a,... Level at idle to make the Holley work and he just wanted to get to! 2.73 gear in the problem is in the back a idle discharge located just above the idle transition.! With headers, an edelbrock Victor, Jr. intake, and always balance the changes side to.! A stamped number larger nozzle introduces more fuel earlier while shortening the duration of the shot barrel! Throttle blades to uncover what is called the transition slot, INC. RIGHTS! Slot described earlier hard to tell if your nozzle is too large too! Over two weeks for edelbrock to reply to my email, they said that they no nonger reply to email... Pump arm and the problem is hesitation on acceleration fron stop after the engine is receiving...

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