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:rolleyes:

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.

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.

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?

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

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

Re: Backfire Thru Carb
 

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