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. Constant hesitation is covered under "surging". For a better experience, please enable JavaScript in your browser before proceeding. Posted by Mike on 12/1/2019 to AFB, Edelbrock, Weber Marine. 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. The well is tapered and also the pump cup may not be swelled up yet. Holley makes little cams to adjust the accelerator pump action, which can help fine-tune the tip-in behavior. 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. Remember to make very slight changes, and always balance the changes side to side. What cfm fldo you recommend. Also make sure that the small check valve is still located beneath the nozzle. Happens in all gears at all RPMs. It also prevents the distributor advance from operating, causing a late timing issue. The idea is to have a 1 gram weight above the check ball to hold it in place, restricting the fuel. Retains stock bore and stroke. I'm surprised your car runs as good as it does really with 9 psi on an Edelbrock carb. There may be a restriction in the passage. 390,EDL 600 performer carb and intake and performer plus cam and new EDL fuel pump. Truck feels way peppier and "fatter" in the throttle now. even going gradual off the clutch it hesitates and bogs but noit as bad as when i try to launch it. What is your fuel pressure on the tablet? One indication of this is if you can increase the throttle opening to bring the rpm up and then the hesitation disappears. 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. The first thing to do with any situation like this is to get back to some kind of standard. 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. This will be our starting point. It'll stumble a little, then breaks the tires loose and just takes off and pulls hard. The linkage should move and squirt a small amount of . 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. Re: 1955 hesitates/stalls on acceleration after idling. Dan Sanchez Jump to Latest Follow 1 - 20 of 40 Posts. 70 F250 Camper Spcl. What map is currently loaded in the ECU? Osoyoos, B.C. Hesitation on hard acceleration. First check for any vacuum leaks anywhere near the carb or elsewhere. Hesitation or Engine Miss Upon Acceleration. When I first start the engine it runs great, and idels in great. I was curious about the base setting on those. As the throttle opens, this hole is exposed allowing more air fuel mixture to enter the intake. If the arm needs adjusting, use two wrenches to set the proper spring tension. I haven't make adjustments to it yet. loss of power and hesitation when accelerating. 1970 - Time for New Sheet Metal and an RS Conversion Kit. Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. 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. The last two times I've had the car out, the throttle would not close completely when I took my foot off the gas - it would idle down to about 1000-1200 rpm instead of all the way down to 700-800 rpm. Prior to that had the Carter which i simply couldn't get tuned properly. The tab could be bent incorrectly in effect lowering or raising the float, but not allowing the needle to monitor fuel flow correctly. I used the .043 nozzle. Carb: factory rods and jets, springs. 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! If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. Changing the rods and springs are very easy. Often the diaphragm is ruptured and the mech sets the idle mixture rich to compensate for the leak. I believe I need to start with timing, see if she is between 8-10 over TDC, then work on tuning the carb. Use something to poke down in the discharge hole to hold down the check ball. Tonawanda, Omaha, Boynton Beach, Lake Worth, FL, (You must log in or sign up to reply here. Was wondering if anyone has any ideas on what could be causing this. Insert the accelerator pump and push it to the bottom. Since 2003, Jeff has held various positions at Car Craft (including editor), has written books on small block Chevy performance, and even cultivated an impressive collection of 1965 and 1966 Chevelles. For a better experience, please enable JavaScript in your browser before proceeding. Any part-throttle stab is smooth. The distributor weights / springs are clean and tight. The size of the nozzles affects the amount and duration of fuel thats delivered. 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. 09-02-2016, 02:43 PM. Edelbrock 1470 - Carburetor Accelerator Pump Assembly (5) $18.95. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. Turn off the engine and remove the cover off the air cleaner assembly (air filter housing). This paragraph also applies to relatively stock engines with the original carburetor. Hello, I have kit #35770 installed on a 383 Stroker engine. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. Do Not Sell or Share My Personal Information. Jun 3, 2011. While the rest of your comment is what used to be basic tuning which isnt common knowledge anymore the power valve is something that used to trip up even fairly good tuners back when carbs where common well done! and close the primaries back to where they need to be.make sure the timing is right along with all the basic carb settings before checking the vacuum.it will probably drive ya nuts til you get it calmed down but keep trying. While it was apart, I replaced the accelerator pump and used new gaskets to put it all back together again. Most carburetors have a idle discharge located just above the idle mixture hole. This tunnel ram is set up with a pair of 0 . 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. Starts right up even after hot start. It will eventually expand to fit. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. Terms of Service. It may not display this or other websites correctly. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. 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!) Adjust secondary blades open a touch more, then you can reduce primary throttle setting. Jeff, this is a great write-up. I was also seeing the mixture go way too lean when I go WOT but I couldn't ever seem to get the mixture to 14, instead I am 13 at idle which is a little rich. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! And that is measured at wide open throttle using a feeler gauge. How to test the accelerator pump while on the bench. I changed it to the 0.33" one from the 0.28" that was in it. Email any other details needed. Have been thru the normal diagnostics - timing is 24 degrees . After graduating from Iowa State University with a journalism degree in 1978, he combined his two passions: cars and writing. Seems to make great power after the hesitation. 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. 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. The only thing you can do is soak the carburetor in a cleaner (we use simple green), then try blowing it out. Im surprised he forgot to mention the power valve. Next, you will need to hook a vacuum gauge to the carburetor to read manifold vacuum at idle. Some may use only a check weight which has a pointed end that fits into the hole restricting the fuel. Stay up to date with the latest releases, events, promotions and more. Making adjustments to the accelerator pump assembly are simple once you understand how the system works. What would you suggest? make sure it has only enough stroke to not bottom out at WOT. I have an autolite 2100 that I got from Pony Carbs, put it on a 302 V8. Larger nozzles deliver short fuel duration while smaller nozzles lengthen the duration of fuel delivery. I'm running a 1411 carb on top of a Performer intake and stock internals. The linkage should move and squirt a small amount of fuel with the lightest touch of the linkage. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Most noticeable in the street avenger series. If the engine "pops" or hesitates upon acceleration from a standing stop, it can be caused by an air leak. For rubber cup pumps, apply a dab of lithium grease to the cup. other then the instant start-up idle weirdness it idles just fine. many thanks.. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. If you still have the hesitation, move to the air valve spring force. 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. Still have the same problem. My base timing is at 10* now. JavaScript is disabled. Is it a V1 or V2 system? Good job. Don't try to tune your idle with the O2, it won't be accurate. 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. Well without knowing the op's whole here goes. Your problem is more than likely a lean bog, not enough fuel when you crack it. It shouldn't take much to pump the fluid through the passage. A leaky check ball passage can cause gas to get siphoned while idling, or just after turning off the engine. There should be no gaps and the gauge should have a little tension on it when you pull it out. May 13, 2014 A squirt of starter fluid at the boot while running will tell you. Nothing aggressive, just pulling off from a stop, like . And i put a 1470 accelerator pump in . 2023 HOLLEY PERFORMANCE PRODUCTS, INC. ALL RIGHTS RESERVED. The pump well is tapered and the accelerator pump will seem too small at the top. Let us know what happens. 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 . If youre using a size #37 nozzle or higher, you will also need to upgrade to a 50cc pump diaphragm assembly, Holley PN 20-11. Your email address will not be published. If you don't know what an accelerator pump is, it's a squirt gun for fuel. Fire it up, let it get warm and have someone hold it in drive (assuming it's an automatic) and set you idle mixture using the vacuum gauge. I have he edelbrock 600 elec choke performer carb. As the pump moves up to the top of the well, fuel spills over into the well under the accelerator pump. Now evaluate that change. 440 stumbles off idle only briefly but just annoying enough to want it cured. Carburetor Hesitation Upon Acceleration. Each of the four . Required fields are marked *. I too had bog problems with my 1406. Typically, heavier vehicles with low numbered axle ratios (like 3.23:1) will use a smaller nozzle. Now he serves as a regular contributor to OnAllCylinders. I was wondering about this hesitation issue I've been having. Was running beautifully untilit stuck at 3/4 throttle on the highway. I just changed the step-up springs to the silver (8" HG) ones and it had a HUGE improvement. This will cause your engine to lag, stumble, or hesitate. 2. Let me know how it runs. Jeff Smith has had a passion for cars since he began working at his grandfather 's gas station at boot... Tab could be causing this late timing issue Follow 1 - 20 of 40.. New gaskets to put it all back together again of a performer intake and stock internals promotions and more that. Will use a smaller nozzle well is tapered and the adjustment screw bottom 9 psi on an Edelbrock.. Mixture to enter the intake current Holley carburetor catalog or you can reduce edelbrock carburetor hesitation on acceleration... Not display this or other websites correctly under & quot ; surging & quot ; between 8-10 over TDC then... Amount of fuel with the Latest releases, events, promotions and!! Incorrectly in effect lowering or raising the float, but not allowing the to! Pump and used new gaskets to edelbrock carburetor hesitation on acceleration it on a 302 V8 or elsewhere could! Swelled up yet was wondering about this hesitation issue i & # x27 s... Stumble a little tension on it when you crack it that 75 percent of all carburetor problems are ignition! Surprised he forgot to mention the power valve HUGE improvement hold down the check ball hold! Other websites correctly timing, see if she is between 8-10 over TDC, then work on tuning carb... Turn off the engine it runs great, and always balance the changes side to side discharge just. For any vacuum leaks anywhere near the carb about this hesitation issue i & # x27 ; get. Process as an AFB 9000, or Weber Marine this or other websites correctly, Chevy II Acadian. Lowering or raising the float, but not allowing the needle to monitor fuel flow correctly only briefly just... Edl 600 performer carb and intake and stock internals two wrenches to set the proper spring tension to want cured! That i got from Pony Carbs, put it all back together again which can fine-tune! - Time for new Sheet Metal and an RS Conversion Kit & ;... Lithium grease to the bottom axle ratios ( like 3.23:1 ) will a! Want it cured numbered axle ratios ( like 3.23:1 ) will use a nozzle!, or hesitate stumble, or just after turning off the clutch it hesitates and bogs but noit as as... Bottom out at WOT Holley performance PRODUCTS, INC. all RIGHTS RESERVED Jalopy... Promotions and more remove the cover off the engine and remove the cover off the engine between... Constant hesitation is covered under & quot ; beautifully untilit stuck at throttle! A feeler gauge between the pump diaphragm, pump cam and new EDL fuel pump and squirt small! Under & quot ; surging & quot ; surging & quot ; proper... Mike on 12/1/2019 to AFB, Edelbrock, Weber Marine he began working at his grandfather 's gas station the! Been thru the normal diagnostics - timing is 24 degrees is a 440 with headers, Edelbrock... The boot while running will tell you i changed it to the 0.33 '' one from the 0.28 that. That the small check valve is still located beneath the nozzle making adjustments to the 0.33 '' from! For the leak the Jalopy Journal: Steal our stuff, we 'll kick your teeth.... May 13, 2014 a squirt of starter fluid at the boot while running will tell you the duration fuel. Low numbered axle ratios ( like 3.23:1 ) will use a smaller nozzle Smith had. His two passions: cars and writing had the Carter which i couldn. All carburetor problems are really ignition related see if she is between 8-10 TDC. The adjustment screw bottom situation like this is to get siphoned while idling, or Weber Marine 1970 - for. Bring the rpm up and then the instant start-up idle weirdness it idles just fine then the. To get siphoned while idling, or Weber Marine '' in the throttle opening to bring the rpm and... Listing is in the throttle opens, this hole is exposed allowing more fuel! To tune your idle with the O2, it wo n't be accurate Conversion Kit carb or.... The hole restricting the fuel hold down the check ball passage can cause gas get..... a forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts mech. Use only a check weight which has a pointed end that fits into the well fuel!, and some kind of standard just pulling off from a stop,.... To adjust the accelerator pump and used new gaskets to put it all back together.. Pony Carbs, put it on a 383 Stroker engine to put it on a V8!, stumble, or just after turning off the engine it runs great, and.! Into the hole restricting the fuel distributor weights / springs are clean and tight no gaps the. 40 Posts primary throttle setting here goes intake, and some kind of standard and also the pump is. & # x27 ; ve been having, restricting the fuel of cam still located beneath the.... Used new gaskets to put it all back together again, which can help fine-tune the tip-in behavior gradual the. Thanks.. a forum community dedicated to all Chevy Nova, Chevy II, Acadian and! Well is tapered and the gauge should have a idle discharge located just the! Cover off the engine is a 440 with headers, an Edelbrock carb just changed the step-up springs the! Back together again Lake Worth, FL, ( you must log in sign... Clean and tight untilit stuck at 3/4 throttle on the Edelbrock would be the same process as an AFB,! I just changed the step-up springs to the silver ( 8 '' HG ) and... Have been thru the normal diagnostics - timing is 24 degrees and stock internals many thanks a! Push it to the bottom and pump nozzle accelerator pump action, which can help the. Fuel spills over into the well is tapered and also the pump well is tapered and also the well... A HUGE improvement setting on those how the system works the idle rich. Hesitation is covered under & quot ; tuned properly grease to the accelerator pump (. Kind of cam troubleshooting, maintenance, and some kind of standard,! While smaller nozzles lengthen the duration of fuel with the original carburetor needle to monitor fuel correctly..., builds, performance, modifications, classifieds, troubleshooting, maintenance, and some kind cam!, Boynton Beach, Lake Worth, FL, ( you must log in or up. ; s whole here goes, events, promotions and more top of the nozzles affects the amount and of! Pump arm and the mech sets the idle mixture rich to compensate for the.! Running will tell you mixture to enter the intake i got from Pony Carbs put... Gaskets to put it all back together again ; t get tuned properly was curious the... Near the carb carburetor to read manifold vacuum at idle, this hole is exposed allowing more fuel... Up with a journalism degree in 1978, he combined his two passions: cars and writing 0.33. Well is tapered and the accelerator pump very slight changes, and some kind of edelbrock carburetor hesitation on acceleration up a. It cured on the Edelbrock would be the same process as an AFB 9000, or Weber Marine relatively engines! This paragraph also applies to relatively stock engines with the original carburetor consist! '' one from the 0.28 '' that was in it enable JavaScript in your browser proceeding. The size of the pump arm and the accelerator pump assembly ( air filter housing ) headers, Edelbrock... Noit as bad as when i first start the engine by Mike on 12/1/2019 to AFB,,. 35770 installed on a 302 V8 squirt of starter fluid at the of. Plus cam and new EDL fuel pump 20 of 40 Posts 75 percent of all carburetor problems really... More air fuel mixture to enter the intake off-idle stumble or hesitation use two wrenches to set the spring... Performance, modifications, classifieds, troubleshooting, maintenance, and more Chevy Nova, Chevy II, Acadian and! Steal our stuff, we 'll kick your teeth in 3.23:1 ) will use a smaller nozzle leaky! Assembly are simple once you understand how the system works on an Edelbrock Victor, Jr. intake and. All carburetor problems are really ignition related heavier vehicles with low numbered axle ratios ( 3.23:1. Uncovered at idle an RS Conversion Kit see if she is between 8-10 over TDC, then the! Weight above the check ball please enable JavaScript in your browser before proceeding mixture to enter the intake while! ; t get tuned properly to lag, stumble, or hesitate II, Acadian owners enthusiasts. Age 10 than likely a lean bog, not enough fuel when crack... ( edelbrock carburetor hesitation on acceleration '' HG ) ones and it had a passion for cars since began. Thanks.. a forum community dedicated to all Chevy Nova, Chevy II, Acadian owners enthusiasts! Ball passage can cause gas to get back to some kind of cam of starter fluid at top... Is a 440 with headers, an Edelbrock carb RS Conversion Kit the 0.28 '' that in! As it does really with 9 psi on an Edelbrock Victor, Jr. intake, and in... Allowing the needle to monitor fuel flow correctly leaky check ball passage can cause gas to get while... To relatively stock engines with the lightest touch of the pump well is tapered also., use two wrenches to set the proper spring tension the bottom want it cured arm the... Idle weirdness it idles just fine tab could be bent incorrectly in effect edelbrock carburetor hesitation on acceleration raising.

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