Backfire Thru Carb
05-12-2004 | 06:33 PM
#13
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From: Houston, TX, USA
Originally posted by cuda
I don't know if this applies in your case, but in cars, the first thing I suspect with backfiring thru the carb is lean fuel mixture. Second thing is the timing off. The third is crossfiring.
I don't know if this applies in your case, but in cars, the first thing I suspect with backfiring thru the carb is lean fuel mixture. Second thing is the timing off. The third is crossfiring.
05-12-2004 | 08:35 PM
#14
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Joined: Dec 2003
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From: La Grange Ill
If it's backfiring under 2000 rpm, when trying to go on plane, it's possible you're puttin too much load on the engine.
When you lug a engine too much at a low rpm, it WILL cause a slow constintant backfire.
If it is a rapid backfire, start lookin toward the ignition for the problem.
These are some of the problems I have encountered in the past years. And I am assuming the problem goes away once you're on plane.
Try: trimming the drives a little more, when going on plane, so the props slip a little more, and see if that helps. If it does, you might have too much cup in your props.
Just speakin from experience, Frank.
When you lug a engine too much at a low rpm, it WILL cause a slow constintant backfire.
If it is a rapid backfire, start lookin toward the ignition for the problem.
These are some of the problems I have encountered in the past years. And I am assuming the problem goes away once you're on plane.
Try: trimming the drives a little more, when going on plane, so the props slip a little more, and see if that helps. If it does, you might have too much cup in your props.
Just speakin from experience, Frank.
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05-13-2004 | 02:47 PM
#15
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From: Newport Beach / California
Originally posted by Turbojack
This was my first though as I was reading all of the posts. If pop is when you press down on the throttle the engine is going lean & thus the backfire. I will say you have bad or sticking accelerator pump or something in that area.
This was my first though as I was reading all of the posts. If pop is when you press down on the throttle the engine is going lean & thus the backfire. I will say you have bad or sticking accelerator pump or something in that area.
I would agree with a lean fuel mixture if it had happened at a higer rpm, but the fact that it happened at 2,000 would lead me to cross firing.
I would check your plug wires and change the distributor cap. Was it a really loud backfire, or a small pop. If it was a small pop your power-valves are probably still ok.
When she does start is she running rich?
05-17-2004 | 05:31 PM
#17
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From: Houston, TX, USA
Re: Backfire Thru Carb
[QUOTE=Krumbsnatcher]I would agree with a lean fuel mixture if it had happened at a higer rpm, but the fact that it happened at 2,000 would lead me to cross firing.
QUOTE]
Nope, lean mixture will cause backfire from just off idle & up
QUOTE]
Nope, lean mixture will cause backfire from just off idle & up
