Truck feels way peppier and "fatter" in the throttle now. I'm getting a slight stumble when I crack the throttle open really quick. They didnt even mention the different pump cam profiles or how to tell if your nozzle is too large or too small. . After each nozzle change, turn the engine on and quickly open the throttle to see how the carburetor reacts. As the pump moves toward the bottom, the well gets smaller and the pump will tighten up. sggoat, ErikinSC and Solace in Solitude. 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. Free shipping. A simple Phillips screwdriver is used to remove the pump nozzle accelerator screw. Any part-throttle stab is smooth. 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). It may not display this or other websites correctly. Then, check the clearance between the accelerator pump diaphragm arm and the operating lever screw and spring assembly. 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. Fuel octane rating makes no difference. If you find it necessary to replace the vacuum . Get cruise voltage at .450 Volts and WOT at around .880-.930 volts. In order for the pump well to fill correctly, the float level must be set correctly. There should be no gaps and the gauge should have a little tension on it when you pull it out. William If you still have the hesitation, move to the air valve spring force. 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. Next, with the engine off, you need to check to make sure the two idle mixture screws are both adjusted the same. Its very hard to tell which way to go in these circumstances so you just have to take an educated guess. Also use the hole closest to the carb for the linkage. This will make the leather too spongy and will probably fail. Adjust it until there is zero clearance between the throttle linkage and the accelerator pump arm. Push the pump down and watch it squirt gas out of the main discharge. Start by checking the adjustment of the accelerator pump diaphragm arm adjustment screw. Next test is to see if the discharge check is working. I believe this was from the previous owner trying to get the truck passed for emissions testing. New edelbrock carb causes backfires. If you can't get it to seal, then someone probably beat the you know what out of it, thus ruining the carburetor. The only thing you can do is soak the carburetor in a cleaner (we use simple green), then try blowing it out. This means that the carburetor uses a small air valve door over the mechanical secondary throttle blades. We pulled over and there were no external issues. glad to hear you got it going! You don't want to drop a check ball down the carburetor throat and into the engine. There is a 4 hole wooden spacer under the carb now. 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. Just install a heat insulator block between the carb and intake. You must check this with the vacuum advance disconnected. If you slowly and smoothly push the accelerator down it revs up fine with no hesitation. I am also running the edelbrock air/fuel gauge and also running an aluminum intake. Has anyone dinked with the secondary tip-in weights? As far as carb size goes, there is a formula that will get close. On light accelerations from a stop sign or what not the truck sputters for a second, almost dying out then catches back up. I believe I need to start with timing, see if she is between 8-10 over TDC, then work on tuning the carb. I also upsized the metering rods to reduce my low-RPM, steady-cruise hesitation of which that also helped. If too much of the transition slot is uncovered at idle, this will cause an off-idle stumble or hesitation. Also don't discount the discharge cover. Report back. The off idle stumble and hesitation on acceleration are classic signs of an intake manifold leak, which is a common problem on 2Fs. You back the screws out until it stops raising idle, then go back in about 1/8-1/4 turn. Changing the rods and springs are very easy. Also, the shorty headers don't scavenge the exhaust as well as long tubes. Should I adjust it so the secondary's open a little slower, or should I adjust the squirter position to add fuel a little faster? Timing: 8 degrees advanced. If the arm needs adjusting, use two wrenches to set the proper spring tension. The Edelbrock AVS2 carb was a great choice for your 383. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! ). Installed a new 1406 on my 63 Avanti. Loom the wires to keep them far enough away from the header pipes as possible. JavaScript is disabled. 2. Your email address will not be published. Jun 3, 2011. Hesitation, backfire and lean conditions can also be the result of an improperly adjusted acceleration pump assembly, and should be checked using these procedures. Jan 25, 2015. Hesitation on hard acceleration. Is it a V1 or V2 system? elcamino65Memberfrom washington. For a better experience, please enable JavaScript in your browser before proceeding. 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. I am fairly new at this, have not done it in years! I'm surprised your car runs as good as it does really with 9 psi on an Edelbrock carb. Primary jet 72, Secondary jet (plate) 75*, Power Valve 6.5, Accelerator pump 31. It may have been changed to a larger one, which is often the wrong move. Good deal! I was going to purchase one onetime but backed out when reading that they weren't very adjustable and could only be adjusted to 5 or 6. All times are GMT-8. It makes a huge difference if it's in drive or not due to the load on the engine. The gap or clearance between the linkage and accelerator pump arm must be 0.012 0.015. Thanks so much for the reply. Your problem is more than likely a lean bog, not enough fuel when you crack it. Any suggestions? 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. 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. A forum community dedicated to hot rod owners and enthusiasts. Even if I'm driving at 20 MPH and open the throttle all the way very quick. 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 . Its pretty specific in the manual to run no more than 6 psi, more like 5 or 5.5 psi. If it still bogs, you probably need a bigger squirter. Was running beautifully untilit stuck at 3/4 throttle on the highway. 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. This tunnel ram is set up with a pair of 0 . 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. 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. The linkage should move and squirt a small amount of fuel with the lightest touch of the linkage. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Other then the slight stumble, the carb runs great. The overall objective is to deliver the right amount of fuel. Thats what causes the bogging and poor throttle response. What map is currently loaded in the ECU? A forum community dedicated to hot rod owners and enthusiasts. Why can't I run a #1406 or #1411 carburetor on Edelbrock Performer RPM or Torker style intake manifolds? The accelerator pump function, as mentioned . I used the .043 nozzle. 1970 440 stock manifold with edelbrock performer 1407 carb. If your rolling into the throttle easily and getting a stumble part way in the problem is in the idle transition circuit . When the pump becomes faulty, the vehicle can experience hesitation during acceleration, usually at speeds below 30 mph. 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. Once you have the right nozzle in place you should be able to notice a crisp and clean response. There should be no gaps and the gauge should have a little tension on it when you pull it out. 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. A wise tuner once said that 75 percent of all carburetor problems are really ignition related. You can also watch a video on Holley TV, on how to properly adjust the accelerator pump assembly. Terrible stumble off the hit . Happens in all gears at all RPMs. I've read this before when searching but no one says. 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. Have you experimented with any spacers under the carb? 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. Any suggestions? Its definitely worth the effort to make this happen. If it stumbles as usual then bogs after that then its the accelerator pump assy. many thanks.. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. We just need to run you through eliminating the problem area. As it deteriorates and cracks, it will leak. Increasing the idle jets in the metering block solves this issue. 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. Thats what causes the bogging and poor throttle response. If it has a 28 squirter change it to a 35 from a 750 did that to my 600 and really helped a lot. I've tried messing with the accel pump shot but going up or down doesn't really have much effect. These tunin. 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. Do Not Sell or Share My Personal Information. Brand new Edelbrock AVS2 series 650cfm carb. Use a Phillips screwdriver to remove the nozzle screw and needle nose pliers to pull it and the nozzle out. Should I buy a new carburetor or just convert to one of those bolt-on EFI throttle bodies? Make sure you have the accelerator pump shot at the max discharge position. I'd put a regulator on there anyway just to make sure thats not an issue. JavaScript is disabled. . Home . Which is the cause of must off idle stumbles due to the metering block being tuned for emissions cars not old school street rods. Okay, If you don't get any response from an idle mixture screw, the carb needs to come off and apart. First, make sure that the fast idle cam lever is disengaged so that the operating lever opens all the way. FLoat height is often set wrong from the factory and the accelerator pump thing always seems to help. Let me know how it runs. I have 2 edelbrock 600s on my hot rod and it runs like a raped ape. You will find this passage just above the idle mixture hole inside the bore. 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