[darrylkmc]

Jim Kroeger

Sounds to me like a lean condition.

I would check to make sure that you have good fuel flow to the carburetor.

More than likely you have crud in the jets of the carburetor which is causing your back fire, if you have good fuel flow, drop the bottom of the carb and take a look. You may have to pull the jets to make certain that they are not plugged.

Sometimes junk is just floating around in the bowl and need to be dumped out. This can cause an intermittent problem as you are describing.

"Also, when installing the new manifold there wasn't a flange between the manifold end and the tailpipe. "

Tailpipe should be flanged and mate-up directly to the manifold, held in place by the muffler clamp.

Darryl in Fairbanks