There may be a check ball with a small check weight above it. Jump to Latest Follow 1 - 20 of 40 Posts. With the car idling you can spray carb and choke cleaner around where the carb seats on the . What map is currently loaded in the ECU? 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. Other then the slight stumble, the carb runs great. I think a 600 to 650 carb will yield better off the line and cruise performance. 350 SBC, 1406, RPM Air Gap, 487 heads, 9.1 cr, pretty much everything else is stock except for MSD ignition. After all is said and done, this is too large and over-cammed an engine (seemingly) for a dopey vacuum secondary carb. Location. She stumbles and hesitates under normal acceleration. When the pump becomes faulty, the vehicle can experience hesitation during acceleration, usually at speeds below 30 mph. I upsized the accelator pump itself when I found one nozzle clogged and rebuilt my carb. Off idle transition is good except with a very slight stumble only if I floor it from idle, much less than when rolling. No fuel coming out means you have a restriction between the pump well and the main discharge. 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. 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. The gap or clearance between the linkage and accelerator pump arm must be 0.012 0.015. Do this for both the primary and secondary float levels, and after changes, make sure the float level is correct. $385.95. Today's gas has very little lubricant causing premature pump failure. Proper accelerator pump adjustment helps in both street and strip applications. We pulled over and there were no external issues. Hey guys Q; My AVS2 runs fine, however when I am on higher speed (70 MPH and up) it starts to hesitate when I step on the gas as well.it just stops performing..what could the probleem be? Be sure to also clean the lines and fuel pump, replace fuel filters and overhaul the carburetor. Turn off the engine and remove the cover off the air cleaner assembly (air filter housing). If I brake hold it to just about anything else above idle and stab it then everything is instantaneous and no hesitation. 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. Nothing aggressive, just pulling off from a stop, like . When you purchase through links on our site, we may earn an affiliate commission, which supports our community. In the center of the overall grid is the number 1, which is the stock metering combination for this carb. The engine is a 440 with headers, an Edelbrock Victor, Jr. intake, and some kind of cam. 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. Rhansen. 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. These tunin. other then the instant start-up idle weirdness it idles just fine. My 1406 carb hesitates (a little) if I stab it to the floor below ~3500 rpm. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. It hesitates and backfires when I am accelerating at low speed but runs fine at wot. Backfires occur in engines with severe malfunctions, such as those with diverter valve issues, exhaust leaks and faulty catalytic converters. The problem is hesitation on acceleration fron stop after the engine is warmed up. Like the Rochester Q jets. Your email address will not be published. The accelerator pump function, as mentioned . And i put a 1470 accelerator pump in . Edelbrock 1468 . The Fora platform includes forum software by XenForo. Typically, heavier vehicles with low numbered axle ratios (like 3.23:1) will use a smaller nozzle. This page was generated at 01:20 PM. As the throttle opens, this hole is exposed allowing more air fuel mixture to enter the intake. 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. Start the engine and try turning both idle mixture screws in about 1/16-turn (this is a very slight movement). This door is designed to open against spring pressure only after the secondary throttle blades are fully open. Good luck, burn rubber. Just install a heat insulator block between the carb and intake. As far as the carb leaking fuel, depending on where the leak is from, that may be the source of your vacuum leak. . If you slowly and smoothly push the accelerator down it revs up fine with no hesitation. For a better experience, please enable JavaScript in your browser before proceeding. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Also it may not squirt until the pump is part way down the well. Dec 14, 2001. 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 well is tapered and also the pump cup may not be swelled up yet. You are using an out of date browser. No, as in driving the car on the street. The proper adjustment prevents the diaphragm from getting stretched to its maximum limit at wide open throttle. The hole closest to the pivot point on the plunger lever is that setting. 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! Privacy Policy. I've tried messing with the accel pump shot but going up or down doesn't really have much effect. Terms of Service. Some may use only a check weight which has a pointed end that fits into the hole restricting the fuel. One question I have is I have a Holley 110? Tbucket 350 cam do not no specs offenhauser cross ram 2 600 vacuum secondaries. If I go from a stop with mid throttle, she takes off smoothly right away with . The ball will most likely come out. You can check this by hooking up a timing light and watch the timing mark move when increasing engine RPM. If it still bogs, you probably need a bigger squirter. If the throttle response and acceleration is not crisp and clean, then the pump size may be too large. You must log in or register to reply here. The springs that were in there seemed to be the same as the weakest (3" HG) springs in the calibration kit! 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. Report back. Was wondering if anyone has any ideas on what could be causing this. Do you think I would benefit from the regulator? What happens is this. 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. Increasing the idle jets in the metering block solves this issue. Insert a 0.015 feeler gauge between the pump arm and the adjustment screw bottom. All times are GMT-8. Has anyone dinked with the secondary tip-in weights? The distributor weights / springs are clean and tight. Enter To Win Holley's 2023 Hemi Engine Sweepstakes For Your Chance To Win A 600+ Horsepower 392 Stroker! Most noticeable in the street avenger series. 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. This article leaves out a bunch of detail. There should be no gaps and the gauge should have a little tension on it when you pull it out. We use mineral spirits (odorless) for all of our testing. 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. The off idle stumble and hesitation on acceleration are classic signs of an intake manifold leak, which is a common problem on 2Fs. Executing all these suggestions will be a time-consuming process and not all may contribute to improving drivability. air fuel meter will help determine these easily. Easy to experiment. Makes a poping or pinging sound not a real loud backfire. Off idle transition is good except with a very slight stumble. Well, I am still running a carb plate and phenolic .5" spacer. 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 . Generally I run those at all the way in then 2.5-3 turns back out that is the standard factory setting from edelbrock, The regulator is set up at 4 1/2 lbs I know it can take more but the reg is a cheap thing so I don't believe the settings. make sure it has only enough stroke to not bottom out at WOT. I should check the jets now too. After cleaning it (blow out every little passage possible) put it back on and start with about 1 to 2 turns out on each screw. 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. Larger nozzles deliver short fuel duration while smaller nozzles lengthen the duration of fuel delivery. Thats what causes the bogging and poor throttle response. More than likely there is dirt somewhere. 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. A inline 4 cylinder engine is very close to 6 cylinders, which is exactly like working on a 8 cylinder engine. Another thing, get a vacuum guage to tune your mixture screws with. Jeff, this is a great write-up. There is a 4 hole wooden spacer under the carb now. I reset my timing, insulated some fuel line and it has been running great. That should not happen. Not that I could tell when I had it apart but I did notice the weights were numbered differently (41 and 42 IIRC), don't know if that means anything or not. You will find this passage just above the idle mixture hole inside the bore. We just need to run you through eliminating the problem area. Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. I used the .043 nozzle. We often see where the adjustable spring is set incorrectly. Engine is a 440 with 1.6 exhaust valve,torker intake,headers and a mild . For rubber cup pumps, apply a dab of lithium grease to the cup. If reducing the squirter size worsens the hesitation, then it needs an even larger squirter. Insert the accelerator pump and push it to the bottom. 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. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. 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. I've adjusted the timing to several positions, Readjusted the Holley regulator(lower and higher), Adjusted the air mixture and even went over the valves, All that and still have the problem. My 1406 carb hesitates (a little) if I stab it to the floor below ~3500 rpm. I was wondering about this hesitation issue I've been having. Be careful not to loosen the check valve needle that sits under the nozzle. How to test the accelerator pump while on the bench. I was driving my truck the other day and it felt as though it was running out of gas. See all 12 photos. The Fora platform includes forum software by XenForo. I am fairly new at this, have not done it in years! This slot supplies additional idle circuit fuel in that short movement between curb idle and where the main metering circuit begins to introduce fuel. The formula says that my 307ci motor at 104% VE at 6000 rpms needs a 554 cfm carb. The linkage should move and squirt a small amount of . ). Is it a V1 or V2 system? 1; 2 . Apply a couple drops of oil to the pump. Backfiring caused by incorrect fuel-to-air ratios result from the engine . Also, the shorty headers don't scavenge the exhaust as well as long tubes. Changing the rods and springs are very easy. Just some information for interested parties, the Thunder series has an adjustable air dam mounted above the secondaries. Warm the engine to operating temperature. Your problem is more than likely a lean bog, not enough fuel when you crack it. For a better experience, please enable JavaScript in your browser before proceeding. Your accelerator pump isn't working. Stay up to date with the latest releases, events, promotions and more. Stock is the 5" HG springs. How about the air/fuel screws? I have some ideas, either the carb (edelbrock 650cfm) is screwing . This way, if you get messed up or lost, you can always return to this setting as your baseline. Narrow band only tells rich or lean, bit not how much. As the pump moves toward the bottom, the well gets smaller and the pump will tighten up. I'm having off-idle stumble and there's a stumble when the secondaries come in. But if you stick with it and carefully keep track of the changes and pay attention to what the engine wants, you will discover that the engine will run much cleaner, offer strong throttle response, and will be much more fun to drive. 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. Now evaluate that change. If your secondaries are opening . posted 09-08-2005 04:44 PM. Some AFB's, or Weber Marine use a check ball and a spring. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. 04-20-2010, 09:42 AM. The Edelbrock AVS2 carb was a great choice for your 383. This moves the carburetor into the main metering circuit but light acceleration using this technique is annoying and it merely is a band-aid for the real problem. The first thing to do with any situation like this is to get back to some kind of standard. 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. 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. I have an autolite 2100 that I got from Pony Carbs, put it on a 302 V8. A small engine like that that idles ok but bogs under acceleration is usually one of three things; 1) air leak at the intake boot. If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. 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. The accel pump isn't hard either but you have to take the top of the carb off. Your email address will not be published. Then drop the idle speed to where you want it to idle in RPM and . 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. Turn the screw clockwise (S) will slow the opening rate. May 22, 2010. A squirt of starter fluid at the boot while running will tell you. Its very hard to tell which way to go in these circumstances so you just have to take an educated guess. Do Not Sell or Share My Personal Information. Next, you will need to hook a vacuum gauge to the carburetor to read manifold vacuum at idle. Someone said I might need to advance the timing . After re-reading your initial post, I believe you need a bigger carb. #12. If it has enough overlap for a loping idle, fuel injection wont have enough vacuum to not be a pain in the butt to tune. What are your AFR Targets set to? Tuning the carburetor idle quality by using a simple vacuum gauge can often result in a better setting on the idle circuit. If you press down on the accelerator quickly the engine will almost stall for a second or 2 before it then actually revs up. 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. It just takes a lot longer to really dial in a carburetor compared to fuel injection where you just hit a few keystrokesbut the effort is worth it. 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. For a better experience, please enable JavaScript in your browser before proceeding. Motor pulls clean to 6K, haven't tried taking it higher. If you are installing a #40 or larger pump nozzle you will need to replace the screw with Holleys hollow pump nozzle accelerator screw. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Edelbrock 600 CFM carb, #1405. does edelbrock make a 2 barrel carburetor You could also drill the squirter out with a number drill (I think it's a #59 but it mics at about .032). 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. 10 positive effects of population growth on economic development But I still had a bog at about 1/4 to 1/2 throttle. Any part-throttle stab is smooth. When you have a stuck check ball in the bottom of the accelerator pump well, you have a couple of options to try. 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. Have been thru the normal diagnostics - timing is 24 degrees . This allows maximum fuel to flow through the nozzle. https://forums.edelbrock.com/filedat?photoid=42773, If this is your first visit, be sure to Often this 2-inch flexible fuel line at the tank can be the cause of a lot of carburetion issues. Posted by Mike on 12/1/2019 to AFB, Edelbrock, Weber Marine. The car runs fine once the rpm is up and cruising, but it has a terrible stumble when I hit the throttle. An indication of this would be to see gas dribbling out of the main discharge at idle. I was curious about the base setting on those. Oh yeah lets not forget one good backfire and the powervalve is junk, considering that people have been been playing with this car to find the problem, a backfire isnt out of the question! Terrible stumble off the hit . The bigger ball resides in the main discharge. JavaScript is disabled. Its definitely worth the effort to make this happen. Free shipping. Tips and tricks to help you if your carburetor has a bad bog, stumble, or hesitation when you punch the gas. What cfm fldo you recommend. The only thing you can do is soak the carburetor in a cleaner (we use simple green), then try blowing it out. Initial is like 20, advance all in right at 3000 w 36 deg. by coop Tue Dec 29, 2009 8:05 pm. 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. elcamino65Memberfrom washington. I have he edelbrock 600 elec choke performer carb. check out the. Its a Edelbrock 1406 model. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. It has a flat spot/hesitation before taking off. It also prevents the distributor advance from operating, causing a late timing issue. 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. Set them both the same at about 1 turns counterclockwise from fully seated. We will discuss two types of bog: the . Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! Constant hesitation is covered under "surging". Fuel octane rating makes no difference. 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. Krawk101 8 mo. 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!) Why can't I run a #1406 or #1411 carburetor on Edelbrock Performer RPM or Torker style intake manifolds? Acompanhe-nos: bonsall oaks development Facebook. I just didn't know If the cheap one was a good idea. Happens in all gears at all RPMs. If you still have the hesitation, move to the air valve spring force. many thanks.. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. If you can't get it to seal, then someone probably beat the you know what out of it, thus ruining the carburetor. That makes good sense. What is your fuel pressure on the tablet? 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. Your carb should have an instruction book on how to adjust it. Sounds like your on to something! 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 . loss of power and hesitation when accelerating. (Image/Holley). . 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. even going gradual off the clutch it hesitates and bogs but noit as bad as when i try to launch it. I also upsized the metering rods to reduce my low-RPM, steady-cruise hesitation of which that also helped. A new leather cup type of accelerator pump will need to eventually expand. It's set up the way it cam out of the box other then the idle and idle mixture settings. What would you suggest? Put a double pumper carb up there, maybe an 850 (like a chokeless HP) and watch that flat spot disappear. Loom the wires to keep them far enough away from the header pipes as possible. Please note, it may never fit tight and isn't supposed to. 2. The goal is to deliver the right amount of fuel at the right time. Use a Phillips screwdriver to remove the nozzle screw and needle nose pliers to pull it and the nozzle out. And that is measured at wide open throttle using a feeler gauge. Truck feels way peppier and "fatter" in the throttle now. He couldnt fit a spacer under the carb (my dad made a wooden one just for test purposes). do koalas have poisonous claws. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); I agree to receive emails from RacingJunk.com. The Holley accelerator pump assembly that consist of the pump diaphragm, pump cam and pump nozzle. 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. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. What should it be?^^. Any part-throttle stab is smooth. about 3200 rpm, I can hear the secondaries starting to kick in and then it stops accelerating and alternately bogs/surges but won't accelerate unless I lift off the throttle. 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! Be patient, you'll get through it. After waiting over two weeks for edelbrock to reply to my email, they said that they no nonger reply to emails. Shoot for the highest vacuum and Rpms. 1970 - Time for New Sheet Metal and an RS Conversion Kit. Hesitation or Engine Miss Upon Acceleration. 204 East 15 th Street. "Do you know how whipped an engine has to be to blow that loud? Otherwise this will also cause the engine to bog. Push the pump down and watch it squirt gas out of the main discharge. You need to check the float level and adjust it where the fuel level at idle is just below the removable sight plug. 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. Good job. I'd put a regulator on there anyway just to make sure thats not an issue. You must check this with the vacuum advance disconnected. Privacy Policy. One indication of this is if you can increase the throttle opening to bring the rpm up and then the hesitation disappears.
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