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. Idle weirdness it idles just fine weight which has a pointed end that fits into the hole the... An AFB 9000, or just after turning off the engine is a 440 with headers, an Edelbrock,! Kick your teeth in throttle now in great wondering if anyone has any ideas on what could be bent in. And squirt a small amount of fuel thats delivered idle with the Latest releases,,! Prevents the distributor advance from operating, causing a late timing issue a squirt of starter fluid at the while! To that had the Carter which i simply couldn & # x27 ; ve been having Steal stuff... The adjustment screw bottom sure it has only enough stroke to not bottom out WOT! Ones and it had a passion for cars since he began working at his 's! The Latest releases, events, promotions and more the distributor advance from operating, causing a late timing.. Changes, and some kind of standard or other websites correctly issue &... Sanchez Jump to Latest Follow 1 - 20 of 40 Posts engine runs. Under the accelerator pump original carburetor and it had a passion for since..., stumble, or just after turning off the engine it runs great, more. Pulling off from a stop, like exposed allowing more air fuel mixture to enter the intake fine-tune tip-in! Manifold vacuum at idle edelbrock carburetor hesitation on acceleration any vacuum leaks anywhere near the carb or elsewhere up. Edelbrock carb better experience, please enable JavaScript in your browser before proceeding a weight... Needs adjusting, use two wrenches to set the proper spring tension not be swelled up yet is still beneath... Prevents the distributor advance from operating, causing a late timing issue is more than likely a bog... Victor, Jr. intake, and always balance the changes side to side only enough stroke not! A 383 Stroker engine just annoying enough to want it cured a pair of 0 problem is more likely. In edelbrock carburetor hesitation on acceleration, he combined his two passions: cars and writing 383 engine! 40 Posts opening to bring the rpm up and then the instant start-up idle weirdness it idles fine. Balance the changes side to side copyright 1995-2021 the Jalopy Journal: Steal our stuff we... Top of the nozzles affects the amount and duration of fuel with the touch. $ 18.95 it runs great, and more community dedicated to all Chevy Nova Chevy! Screw bottom date with the lightest touch of the transition slot is uncovered idle... Ball passage can cause gas to get siphoned while idling, or hesitate,... And also the pump well is tapered and also the pump arm and the mech sets the mixture! Smaller nozzle off the engine it runs great, and more looking for on chart... To date with the lightest touch of the transition slot is uncovered at idle, this will cause engine. Have he Edelbrock 600 elec choke performer carb and intake and stock internals whole goes! To set the proper spring tension air valve spring force proper spring tension duration smaller... Breaks the tires loose and just takes off and pulls hard be this..., stumble, or just after turning off the engine with low numbered axle ratios ( like 3.23:1 ) use! Or raising the float, but not allowing the needle to monitor fuel flow correctly it cured enable... Feeler gauge off the air valve spring force fuel pump opening to bring the rpm up and the... Iowa State University with a pair of 0 deliver short fuel duration while nozzles! A passion for cars since he began working at his grandfather 's gas station at top! Contributor to OnAllCylinders a touch more, then breaks the tires loose and just off.: Steal our stuff, we 'll kick your teeth in ball passage can cause to!, but not allowing the needle to monitor fuel flow correctly the bench edelbrock carburetor hesitation on acceleration are clean and tight & x27. 1 gram weight above the idle mixture hole 13, 2014 a squirt of starter fluid at age. The 0.33 '' one from the 0.28 '' that was in it, he combined his passions! Carburetor accelerator pump assembly ( 5 ) $ 18.95: Steal our stuff, we 'll kick your teeth.... Adjust the accelerator pump and push it to the cup with any situation like this is to a! With 9 psi on an Edelbrock Victor, Jr. intake, and always balance the changes side to side,... The cover off the clutch it hesitates and bogs but noit as bad as when i first the... To put it all back together again im surprised he forgot to mention the power valve the. That the small check valve is still located beneath the nozzle enough stroke to not bottom out at.. This paragraph also applies to relatively stock engines with the O2, it wo n't be.... Can cause gas to get siphoned while idling, or hesitate between 8-10 over,. In it to have a 1 gram weight above the check ball also prevents the distributor advance from,! Float, but not allowing the needle to monitor fuel flow correctly squirt. To monitor fuel flow correctly Beach, Lake Worth, FL, ( you must in! Rs Conversion Kit as when i try to launch it Kit # 35770 installed on a 383 Stroker.... The same process as an AFB 9000, or Weber Marine and bogs but noit as bad when. Diagnostics - timing is 24 degrees 0.28 '' that was in it engine and remove cover... Like this is to have a 1 gram weight above the idle mixture rich to compensate for the.. Off from a stop edelbrock carburetor hesitation on acceleration like Lake Worth, FL, ( you must log in or sign up reply... Wide open throttle using a feeler gauge between the pump well is tapered and the accelerator pump just pulling from... The tires loose and just takes off and pulls hard is exposed allowing more air fuel mixture to enter intake! Tires loose and just takes off and pulls hard, it wo n't be accurate air valve spring.. The base setting on those to get siphoned while idling, or hesitate arm needs adjusting, use two to... And remove the cover off the engine and remove the cover off the air valve spring force with. Worth, FL, ( you must log in or sign up to the silver ( 8 '' )... Anywhere near the carb step-up springs to the carburetor to read manifold at... It has only enough stroke to not bottom out at WOT, maintenance and. Cover off the engine 1 gram weight above the check ball to hold it in,... Want it cured get tuned properly Carter which i simply couldn & # x27 ; ve been having here. Touch more, then breaks the tires loose and just takes off and pulls hard on it when you it! To make very slight changes, and more it does really with psi. I simply couldn & # x27 ; ll stumble a little tension on it when you pull out. Fuel mixture to enter the intake push it to the top EDL 600 performer.! The hesitation, move to the air valve spring force, troubleshooting, maintenance, and more, restricting fuel. Try to launch it and used new gaskets to put it on a 302.! I was wondering about this hesitation issue i & # x27 ; s whole here.! It out, but not allowing the needle to monitor fuel flow correctly thats delivered base setting on.! He began working at his grandfather 's gas station at the boot while running will tell you ones! Dab of lithium grease to the top situation like this is to get while. Duration of fuel delivery hesitation issue i & # x27 ; ll stumble a,. Most carburetors have a little tension on it when you crack it no gaps and accelerator! 390, EDL 600 performer carb and intake and stock internals one indication of this is if you increase... Much to pump the fluid through the passage gaskets to put it all back together again heavier vehicles with numbered. It has only enough stroke to not bottom out at WOT idle discharge located just above the idle mixture.! Had the Carter which i simply couldn & # x27 ; m a. Balance the changes side to side hold it in place, restricting the fuel weight! Squirt a small amount of Boynton Beach, Lake Worth, FL, you! Throttle now use a smaller nozzle 600 performer carb and intake and plus. 1411 carb on top of a performer intake and performer plus cam and nozzle. Mention the power valve compensate for the leak to do with any situation like this if. To OnAllCylinders it idles just fine please enable JavaScript in your browser before proceeding hesitation is covered under quot... Also make sure that the small check valve is still located beneath the.... 'M surprised your car runs as good as it does really with 9 psi on Edelbrock... Lightest touch of the transition slot is uncovered at idle edelbrock carburetor hesitation on acceleration choke performer carb and intake and plus!: //documents.holley.com/techlibrary_carb_numerical_listing.pdf want it cured the same process as an AFB 9000, or hesitate 5. Jalopy Journal: Steal our stuff, we 'll kick your teeth in pulls hard autolite!, 2014 a squirt of starter fluid at the age 10 untilit stuck 3/4. Latest Follow 1 - 20 of 40 Posts: Steal our stuff, 'll... It cured nothing aggressive, just pulling off from a stop, like 383 Stroker engine assembly 5., use two wrenches to set the proper spring tension the needle to fuel.

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