Backfire thru carb
05-15-2003, 04:38 PM
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Backfire thru carb
What causes a backfire thru the carb. The motor idles fine and starts fine. I get the backfire when going wide-open from idle QUICKLY. Damn thing makes a hell-of-a lound BOOM and flame shoots out of the carb!!! I can't get it to do it everytime but it seems to stumble most times. Im not sure if this would cause my problem but would plugs that are too cold cause or add to this? I just installed a new distributor and the timing is right on @ 8 degrees. Am I looking at an ignition problem or a fuel problem (lean or rich)....
BH
BH
05-15-2003, 04:47 PM
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The engine is going lean. When you go from idle to WOT the accelerator pump is to pump extra fuel to your engine to keep it from leaning out.
Solution is if this just started & you have done no motor mods then have your accelerator pump fixed on your carb & that will fix problem. If you have done engine mods then need to make another mod to get more fuel to your engine when nailing it. If you have a Holley, there are a number of different cams for the accelerator & there are bigger pumps.
Solution is if this just started & you have done no motor mods then have your accelerator pump fixed on your carb & that will fix problem. If you have done engine mods then need to make another mod to get more fuel to your engine when nailing it. If you have a Holley, there are a number of different cams for the accelerator & there are bigger pumps.
05-15-2003, 08:54 PM
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textbook accelerator pump/power valve has no effect during rapid accel. a little moisture in the carb can stick the needle under the discharge nozzle(holley). easy to check/engine cold,batterys off,flame arrestor off,no cigarrette in mouth,look down carb throat and operate throttle/should see 2 streams of fuel
05-15-2003, 09:25 PM
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I like the "no cigarette in mouth" But repeated backfiring WILL blow a Holley powervalve and then when you call for more fuel, the blown diaphram in the valve doesn't open it and you get lean and more backfire. I do stand corrected about the acc. pump syst., but you DO need to check the powervalve(s) too. --- Jer
05-16-2003, 08:35 AM
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Bad- Habit, aren't you running and Eldebrock marine carb if I remember correctly? Had the same problem with that carb on a 302 in a Mustang I used to have. This was back in the 80's and if I remember correctly, I wasn't getting good fuel pressure and was running lean. Put a high volume electric fuel pump and regulator and solved my problems. Just a thought....
