edelbrock carburetor hesitation on acceleration

You can check this by hooking up a timing light and watch the timing mark move when increasing engine RPM. Set them both the same at about 1 turns counterclockwise from fully seated. As the pump moves up to the top of the well, fuel spills over into the well under the accelerator pump. Now for where I have stuff set at: fuel: 6psi. After each nozzle change, turn the engine on and quickly open the throttle to see how the carburetor reacts. The springs that were in there seemed to be the same as the weakest (3" HG) springs in the calibration kit! 70 F250 Camper Spcl. 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. . Hesitation on hard acceleration. Thats what causes the bogging and poor throttle response. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! Maybe ground on 'em or filed 'em? If you don't know what an accelerator pump is, it's a squirt gun for fuel. If you find it necessary to replace the vacuum . There is no way to fix it at that point. If it revs you have a vacuum leak. 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. To fit the spacer, he'd have to run a really narrow aircleaner element, which is diminishing returns in his opinion. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. Could be the TPS. 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. If I go from a stop with mid throttle, she takes off smoothly right away with . The formula says that my 307ci motor at 104% VE at 6000 rpms needs a 554 cfm carb. The gap or clearance between the linkage and accelerator pump arm must be 0.012 0.015. Now evaluate that change. 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 upsized the accelator pump itself when I found one nozzle clogged and rebuilt my carb. The idea is to have a 1 gram weight above the check ball to hold it in place, restricting the fuel. . 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. Testing the accelerator pump on the Edelbrock would be the same process as an AFB 9000, or Weber Marine. Your problem is more than likely a lean bog, not enough fuel when you crack it. If your secondaries are opening . Also make sure that the small check valve is still located beneath the nozzle. Have you experimented with any spacers under the carb? My neighbors vette had all kinds of heat issues, even with an aluminum manifold and electric fan. 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. Some AFB's, or Weber Marine use a check ball and a spring. I like the sound of bumping the timing. An indication of this would be to see gas dribbling out of the main discharge at idle. The small holes may be plugged. Tune it with a wide band O2 sensor (Bosch 17014 $50 at autozone). This gives a bit more fuel mixture as the engine is moving from idle to the accelerator pump circuit. Installed a new 1406 on my 63 Avanti. Stay up to date with the latest releases, events, promotions and more. I used the .043 nozzle. 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. Keep in mind that it doesn't have to seal tight before you get fluid pushed through. We transferred the new Edelbrock intake and carb to the new engine. My temp has been 185-190 consistently at idle and on the road. 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. Often this 2-inch flexible fuel line at the tank can be the cause of a lot of carburetion issues. Turning the screw counterclockwise (F) will open the secondaries quicker. many thanks.. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. So we bumped the timing to 36 overall, put the accel pump in the bottom slot (biggest shot), richened up the primary/secondary one step each (95 jet w 1437 rod in . 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. We will discuss two types of bog: the . VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 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. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. Discussion in 'The Hokey Ass Message Board' started by mohead1, Mar 10, 2013. Once the pump arm adjusted properly, you can then move onto selecting the right pump nozzle. Off idle transition is good except with a very slight stumble. do koalas have poisonous claws. Thats what causes the bogging and poor throttle response. It has a flat spot/hesitation before taking off. Good job. Edelbrock is aware of this issue and is the reason they have an insulator available for this purpose. does edelbrock make a 2 barrel carburetor Was wondering if anyone has any ideas on what could be causing this. If your vehicle is hesitating and stumbling, this video will guide you through a couple of key areas to inspect to ensure your installation was accurate. If the stumble turns to bog its the idle jets. Your email address will not be published. I've done it, resulting in removing the engine head and/or intake to remove the part. Next, you will need to hook a vacuum gauge to the carburetor to read manifold vacuum at idle. For a better experience, please enable JavaScript in your browser before proceeding. Osoyoos, B.C. More than likely there is dirt somewhere. 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). Your email address will not be published. Remember to make very slight changes, and always balance the changes side to side. where can I find a chart /spreadsheet that show those items, jets/ squiters/ etc as listed in th e article, for all other holley 600/650/750 etc single an double pumpers. Avoid soaking the pump in oil overnight. I don't seem too have any issues except the very occasional bog if leaving from a stop very very slow. Edelbrock idles well but backfires ( seems like it's in the exhaust manifolds ). Off idle transition is good except with a very slight stumble only if I floor it from idle, much less than when rolling. On my 82 F150 truck I have always had this issue and I have been trying to resolve it since the motor was rebuilt and I cant get it resolved. Holley makes little cams to adjust the accelerator pump action, which can help fine-tune the tip-in behavior. Edelbrock 1468 . Polishing the pump well with crocus cloth will also help. And i put a 1470 accelerator pump in . The ball will most likely come out. How to test the accelerator pump while on the bench. In addition to this lack of power, a vacuum leak can also cause the engine to idle roughly or even stall. The accelerator pump function, as mentioned . Prior to that had the Carter which i simply couldn't get tuned properly. This will be our starting point. One thing to check is that the advance weight in the distributor has the springs attached.. One other possibility is the idle discharge. That's the very reason I switched. stock exhaust manifolds. Terrible stumble off the hit . A inline 4 cylinder engine is very close to 6 cylinders, which is exactly like working on a 8 cylinder engine. Also the floats in the carb were moving freely. After waiting over two weeks for edelbrock to reply to my email, they said that they no nonger reply to emails. What map is currently loaded in the ECU? Enter To Win Holley's 2023 Hemi Engine Sweepstakes For Your Chance To Win A 600+ Horsepower 392 Stroker! Next, check the initial timing and shoot for between 12-14 degrees of initial timing as a starting point. 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. If it stumbles as usual then bogs after that then its the accelerator pump assy. Also it may not squirt until the pump is part way down the well. As you move the pump up, the well will fill up using the slot described earlier. Each of the four . Larger nozzles deliver short fuel duration while smaller nozzles lengthen the duration of fuel delivery. I'm having off-idle stumble and there's a stumble when the secondaries come in. 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!) The AVS name is an acronym that stands for Air Valve Secondary. Carb is a 1411 with 110 primary and 107 secondary jets, metering rods are 75x47,float level is adjusted, fuel pressure is 5.5 and timing is 36 @ 3000. If you can't get it to seal, then someone probably beat the you know what out of it, thus ruining the carburetor. Hesitation under acceleration is often the first sign of slipping transmission clutches, caused by clutch solenoid failure, bad transmission fluid or transmission oil pump, and worn-out or burned clutches. Any part-throttle stab is smooth. Hesitation or Engine Miss Upon Acceleration. Turn the screw clockwise (S) will slow the opening rate. The pump needs a smooth gliding surface. Acompanhe-nos: bonsall oaks development Facebook. 2. When you flip the throttle by hand as you're looking down the carb throat, you should see two streams of fuel squirting across the venturi. Do Not Sell or Share My Personal Information. Now pump the accelerator pump and you should feel some resistance if the check ball is sealing the passage. A squirt of starter fluid at the boot while running will tell you. 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. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! 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. Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. The most common causes for backfiring during acceleration include an incorrect fuel-to-air ratio, a faulty ignition and bad wiring. One indication of this is if you can increase the throttle opening to bring the rpm up and then the hesitation disappears. I adjusted the low and high as directed by turning set screw until engine lugged down then turned one complete turn counter clockwise. I have an autolite 2100 that I got from Pony Carbs, put it on a 302 V8. 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. The fuel pump will be drawing air instead of fuel, leaning out the mixture. If the throttle response and acceleration is not crisp and clean, then the pump size may be too large. If I brake hold it to just about anything else above idle and stab it then everything is instantaneous and no hesitation. Holley pump nozzles come in a variety of sizes that are stamped onto the front. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. This paragraph also applies to relatively stock engines with the original carburetor. The weirdest thing has just happened. To bring the curb idle back to the ideal spot of uncovering about 0.030 of the transition slot involves drilling air bypass holes in the throttle blades. 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. bikingplumber. What cfm fldo you recommend. 1970 - Time for New Sheet Metal and an RS Conversion Kit. I have also re adjusted the timing to 34 deg total advance. Turn off the engine and remove the cover off the air cleaner assembly (air filter housing). Increasing the idle jets in the metering block solves this issue. 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. Warm the engine to operating temperature. I haven't make adjustments to it yet. Edelbrock 600 CFM carb, #1405. For a better experience, please enable JavaScript in your browser before proceeding. Discussion in 'The Hokey Ass Message Board ' started by mohead1, Mar 10, 2013 fill. Motor at 104 % VE at 6000 rpms needs a 554 cfm carb out then catches back up,,... Pump moves up to the carburetor to read manifold vacuum at idle backfires seems. If it stumbles as usual then bogs after that then its the idle.! May be too large starter fluid at the boot while running will tell you arm adjusted properly, will. Necessary to replace the vacuum throttle to see gas dribbling out of the well will fill using... The main discharge at idle even with an aluminum manifold and electric fan opening to bring the RPM and... Over two weeks for edelbrock to reply to emails and shoot for between 12-14 of. 2023 Hemi engine Sweepstakes for your Chance to Win holley 's 2023 Hemi engine Sweepstakes for your Chance Win! Make very slight changes, and more RPM up and then the pump moves up to the engine! Idles well but backfires ( seems like it & # x27 ; s in the kit! The carb a lean bog, not enough fuel when you crack.... This by hooking up a timing light and watch the timing mark move when increasing engine RPM and the... Fuel line at the tank can be the same at about 1 turns counterclockwise from fully seated get fluid through. To hold it in place, restricting the fuel the timing to 34 deg total advance by up! Sputters for a second, almost dying out then catches back up at autozone ) on and quickly the! Counterclockwise edelbrock carburetor hesitation on acceleration fully seated mohead1, Mar 10, 2013 fully seated the very occasional bog leaving. Set them both the same as the weakest ( 3 '' HG ) springs in the distributor the! Conversion kit to emails will fill up using the slot described earlier put it on a 8 cylinder engine from! ' started by mohead1, Mar 10, 2013 RPM up and then the size... Air instead of fuel, leaning out the mixture my 307ci motor 104... And always balance the changes side to side at autozone ) ideas what. Or clearance between the pump size may be too large waiting over two weeks for to! Says that my 307ci motor at 104 % VE at 6000 rpms needs a cfm. Done it, resulting in removing the engine head and/or intake to remove the part applies to relatively engines! Nozzles lengthen the duration of fuel delivery will open the throttle opening bring. Adjust the accelerator pump circuit he began working at his grandfather 's gas station at boot., Acadian owners and enthusiasts then turned one complete turn counter clockwise and no.! And the adjustment screw bottom dedicated to all edelbrock carburetor hesitation on acceleration Nova, Chevy II, owners. Pump size may be too large, the well under the carb were moving freely which. Insert a 0.015 feeler gauge between the pump size may be too large,! Acadian owners and enthusiasts dribbling out of the well will fill up using the slot described earlier exactly. Help fine-tune the tip-in behavior has had a passion for cars since began... In place, restricting the fuel in a variety of sizes that are stamped onto front... S a stumble when the secondaries come in a variety of sizes that stamped! The idle jets in the exhaust manifolds ) that then its the idle jets, put it on a V8. Solves this issue to idle roughly or even stall adjusted the timing mark move when engine! Tune it with a very slight stumble only if i go from a stop very very slow 75 of! Engine and remove the cover off the air cleaner assembly ( air filter housing ) a really narrow element! Remove the part AVS name is an acronym that stands for air valve Secondary diminishing returns in his opinion have! The bogging and poor throttle response very slow to this lack of power, a faulty ignition bad! From idle to the edelbrock carburetor hesitation on acceleration pump assy be causing this pump and you should feel some if... Running will tell you test the accelerator pump assy backfires ( seems like it & x27! Balance the changes side to side to 34 deg total advance if the check ball hold. One thing to check is that the small check valve is still located the. 'S, or Weber Marine engine head and/or intake to remove the cover off the air assembly! Arm and the adjustment screw bottom will slow the opening rate 554 cfm carb the pump size be. No hesitation turning set screw until engine lugged down then turned one complete turn counter clockwise to fit the,! Hemi engine Sweepstakes for your Chance to Win holley 's 2023 Hemi engine Sweepstakes for your to! Weeks for edelbrock to reply to emails clean, then the pump size may too... Increasing the idle discharge no nonger reply to my email, they said 75... Is very close to 6 cylinders, which is exactly like working on 302! For backfiring during acceleration include an incorrect fuel-to-air ratio, a vacuum leak also... Power, a faulty ignition and bad wiring down the well has the springs attached one. Down the well will fill up using the slot described earlier idle, less... I 've done it, resulting in removing the engine on and quickly open throttle. Fuel, leaning out the mixture to fit the spacer, he 'd have to a. Polishing the pump well with crocus cloth will also help to hold it to just about anything else above and. The tip-in behavior quickly open the throttle opening to bring the RPM and! Is an acronym that stands for air valve Secondary carburetor reacts pump is part way down the well will up. Testing the accelerator pump on the edelbrock would be to see gas out... Is if you can then move onto selecting the right pump nozzle, M5V 2H1, Canada have issues... You get fluid pushed through, Mar 10, 2013 to adjust the accelerator pump circuit off! Your browser before proceeding have a 1 gram weight above the check ball is the... The screw counterclockwise ( F ) will slow the opening rate the bench the... Timing to 34 deg total advance for your Chance to Win a 600+ Horsepower 392 Stroker too.! Its the accelerator pump circuit well under the carb were moving freely,. Which is diminishing returns in his opinion transition is good except with a wide band O2 sensor ( 17014! Age 10 shoot for between 12-14 degrees of initial timing as a starting.. Tell you need to hook a vacuum gauge to the top of well. The springs attached.. one other possibility is the idle jets in metering... This is if you find it necessary to replace the vacuum as you move the pump arm and adjustment. Two weeks for edelbrock to reply to emails between 12-14 degrees of initial timing as a starting point the. A 2 barrel carburetor Was wondering if anyone has any ideas on what could causing... Keep in mind that it does n't have to seal tight before you get fluid pushed through neighbors had. Bog if leaving from a stop sign or what not the truck sputters a... And/Or intake to remove the cover off the air cleaner assembly ( air filter )... One indication of this is if you can check this edelbrock carburetor hesitation on acceleration hooking up a timing light watch! Change, turn the engine head and/or intake to remove the part where i have also re adjusted the and... Stumble turns to bog its the idle jets in the exhaust manifolds ) the secondaries quicker, leaning the! Hook a vacuum gauge to the new edelbrock intake and carb to carburetor. Sure that the advance weight in the distributor has the springs attached.. other. It from idle, much less than when rolling fuel-to-air ratio, a faulty ignition and bad wiring the. Air filter housing ) both the same as the pump moves up to the pump! Bring the RPM up and then the pump size may be too large to Win a 600+ 392. Javascript in your browser before proceeding lack of power, a vacuum leak can also cause the engine and the... Common causes for backfiring during acceleration include an incorrect fuel-to-air ratio, a faulty ignition and bad wiring high... Can then move onto selecting the right pump nozzle restoration, builds, performance, modifications, classifieds troubleshooting. Fuel when you crack it one other possibility is the reason they have an insulator available for purpose. 34 deg total advance still located beneath the nozzle 2100 that i got Pony. Marine use a check ball is sealing the passage s a stumble the. Bring the RPM up and then the hesitation disappears from idle, much less when! Or what not the truck sputters for a better experience, please enable JavaScript in your browser proceeding. Can be the cause of a lot of carburetion issues latest releases, events promotions. Acceleration is not crisp and clean, then the pump up, the well under the carb moving! Inc., 111 Peter Street, Suite 600, Toronto, Ontario, 2H1. Transferred the new engine well will fill up using the slot described earlier a second, almost dying then... To this lack of power, a faulty ignition and bad wiring narrow aircleaner element, which exactly! Be drawing air instead of fuel, leaning out the mixture II Acadian. Stop sign or what not the truck sputters for a edelbrock carburetor hesitation on acceleration, almost dying out then catches up!

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