Ok, Im not new to gas, but Im sure Im missing something.

I got a sweet used ZDZ80 Super J I got off this site. I was testing a prop a few months back and it throw a blade, and broke off the mount lugsoff the rear of the motor.

So I got a replacement rearblock/plate. from Troybuilt Modles Great guys.

I finily got around to putting it in its bird a TopFlite P47 With the Scale Belia 22X10 4 blade prop.

I have not tuned it for this prop, and I know some peaple have a hard time staring, but she gave me no issues.

While trying to get the high end set she backfired on me once at 3/4 power but once I got it leaned out no more top end issues, she is running sweet/scarry at 6900RPM on this prop with no drop off in RPM.

But some times I can bring it down to idel with no issue, I had it ideling at 2000rpm for 30sec or so and was going to run it up and it started back fireing like crazy and sut off.

I richend the low end a little and it would still back fire like crazy.

So now that im typeing this out, Im thinking I need to lean the low end?

Before it would back fire I had no transishion issues.

What you guys think?</p>