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Edelbrock carb experts only!
I've got a 302/350 hp Engine Factory engine with a 650 Thunder Series AVS carb. From a stop or very slow speed, if you floor the pedal and run through the gears at max RPM, it just screams. If you are cruising between 1500 and 3000 rpm and you suddenly floor it, it bogs briefly and then takes off. I have adjusted the timing, made dizzy adjustments to bring in full advance earlier. Timing is at 16 degrees initial advance and around 40 degrees at 3000 rpm. No pinging on pump 91 octane fuel. Noticed ping at 42 degrees and backed off to 40. I went up to stronger metering rod springs and slightly smaller rods. Adjusted the secondaries to open under very light pressure. Still bogs from mid rpm flooring. Does it need to be richer or leaner to eliminate this condition. What do I change next to correct this condition?
:CRY: |
Try moving the accererator pump linkage rod to a lower hole. I think the 650's come with the rod in the upper of three holes. Try the middle or the lowest hole. If that doesn't work you might need a larger pump nozzle.
Sydney |
I agree with Sydney! You need more fuel squirted sooner from the accelerator pump. The bogging is from a momentary lean condition when the throttle plates are suddenly opened. Hope that helps.
Fred |
I went down this path for many months. I was determined to get it right. I had a 351W from Engine Factory and 750 Edelbrock carb. I spent months with a calibration kit and wideband sensor trying to eliminate the same stumble. It disappeared when I put a Holley 650 on.
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If the stumble only occurs after the metering rod is in cruise mode position, I'd guess it is the springs fault. Most likely it's not the pump shot when everything works fine after accelerating from a stop. Simon |
I happen to be the foremost expert on Edelbrock carburation. I have been giving expert advice and pearls of wisdom for years to members of Club Cobra. So, that being said, let me give you the advice you need to correct your problem.
Take the Edelbrock carb off the motor and THROW IT AWAY! Get a Holley, Demon or AED....you'll be much happier. Roscoe |
I agree with Roscoe, but its an expensive first step!
Instead, I would call Edelbrock. Here is a sentence I copied off their web site ..... If you need to speak with an Edelbrock technician by phone, please call 1-800-416-8628 from 7:00am to 5:00pm, Monday-Friday, PST. |
I hope their tech isn't in New Delhi.......
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Roscoe
Your first post is funny and probably quite accurate. Your second post is just too funny. :LOL: :LOL: :LOL: Wayne |
I took it to a tuner this morning, He agrees with Fred and Sydney. I asked him if he thought a Holley 4150 dp would solve the problem and he said we would use that as a last resort. He likes the Ed carb for street cars. He's going to play with the metering rods, springs and replace the accellerator pump and maybe move the rod up a notch. Not sure if it is a lean or rich bog just yet. Then, if no solution, we're bolting on a 4150 dp and I will sell the Ed to a guy who is having problems with his Holley!
Oh yeah, I forgot, I called the tech line from Ed and he said the same thing. metering rods, springs, accellerator pump up a notch. |
If you are close on the A/F already you probably just need to move the pump to the up a notch as mentioned and go to a lighter spring on the metering rods. That will allow it to open up the jets sooner as you get into the gas from a light cruise.
The Edelbrock may not be a great racing carb, but for the street cars it's by far the easiest to tune. |
I thought a heavier metering rod spring would push the rod up sooner allowing more fuel earlier. A lighter one would allow it to remain closed longer, thus leaner! Is my thinking bassackwards?
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Do the easy fix first....change the AC pump to get more fuel per squirt.
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Oops. Sorry I mispoke there. You are correct. Stiffer spring will open the jet up sooner.
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JHV - Let us know the results of the corrections....
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Will do. I turned it over to a tuner to play with. Will get it back tomorrow with a full report of what he did. He said he solved the problem. We'll see!
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...and peel off that stupid looking red Edeldork emblem on the front of the carb. :D
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Just got it back and it seems to be cured. Had to put in larger primary and secondary jets, smaller metering rod and heavier spring. Replaced the acc pump as well. Secondary spring was too loose also. Raised the float level slightly. Lots and lots of trial and error time spent on making it right.
You should see the bill! Thing runs like a bigger block now. Damn good tuner. Anyone interested in his name or location, just ask. He's in Carlsbad, Calif. and when I picked up my car this afternoon, he was rebuilding and tuning the 6 Weber carbs on a classic Lambo Espada his shop had recently begun to restore. Now, that's a job! He said the same thing the "experts" have said, If this doesn't fix it, we'll put on a Holley and be done with it! He custom builds them for each engine. There goes another grand! |
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I forgot to update my last post.
Finally got the thing running good but it seemed down on power. Very streetable but felt mild. Bought and installed a BG Speed Demon double pumper and WOW what a difference. It woke up the engine and put the smile back on my face. Sold the Ed to a guy with a mustang. Both of us are very happy. |
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