Hi all. I have a 98 wolverine, car was just rebuilt to factory specs, and its backfiring through the exhaust in 4th and 5th gear. Any ideas? Is it running rich or lean, or is the float set improperly?

 

whats the plug look like? should be brown and not sooted up.if its black and sooty its rich if it is light brown too grey its lean.if its not cuttin out till the higher gears,try a fresh plug first, if you havent run it enuff to tell by color yet. you may have gas fouled the first one who rebuilt the carb? are you confident the float level is correct/ and that the float is moving freely?