Ok have a very odd issue I can't seem to figure out. Been working on this quad for weeks now.The issue is that when the quad sits fuel overflows into air box Will run fine from around 1/4 throttle up0-1/4 throttle backfires and just doesn't want to run without putting hand over Air box tube as if it is starving for fuel When I have the tank and carb off I can hook the fuel line to the carb on Pri. and 0 fuel overflows out of the carbI have the vacuum petcock bypassed, have thouroughly cleaned the carb entirely, all seems fineI'm stumped on how fuel floods into the airbox when on the quad but off of the quad the float valve seals as it should and no fuel will flow over As mentioned runs fine from 1/4 throttle up. It will idle for a pretty decent while the eventually stumble and die then you have to hold the throttle open to get it to crank back as if floodedAny help would be great. Thank you all