Carb on right side (across from petcock) cuts in and out when at cruzing speed .When at idle that side sounds like its hickuping. When motor is fully warmed up the rps dubble to 300.Petcock, plugs, plug wires,coils,pionts,condenser,airfilters,intake manafold,are new. Carb HAS BEN REBUILT TWO TYIMES WITH NEW NEDDLE VALVES AND NEW DIAFRAMS.I am at a loss.thanks Kirk