Backfire Thru Carb

[FunHome]

carb. 500 hp's are known for this after idleing for a long time!! And since it did this you'll need to replace the power valve's in the carb.'s

[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.

[Turbojack]

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.

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.

[10x]

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.

[Krumbsnatcher]

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.

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?

[WILDTHING TAZ]

IF YOU ARE RUNNING MSD DIST.& MSD BOX. MAKE SURE THE DIST. WIRER'S ARE NOT CROSSED!!! PURPLE GOES TO GREEN. I DID THIS AND SAME THING HAPPENED. RB

[Turbojack]

[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

[Crazyhorse]

Mitch, give me a call. If you've got a Miller Lite or a Mick Ultra for Barb we can stop over and check a few things out. 738-0474 or 403-3962