A bit of advise on the Briggs and Stratton Vanguard engines, esp. the conversions. On the carb there is a bowl vent nipple (1/4") that is part of the vapor system required on newer engines. On the older tractors that run this engine that nipple is left open for proper bowl venting. The problem is it also allows debris into the float bowl which eventually cause plugging of the very tiny jet bleeds. The fix is to take a piece if 1/4" fuel line and attach one end to the nipple and the other end to a quality metal 1/4" line fuel filter leaving the other end of the fuel filter open. Even something as tiny as the "hair" strand of a grass seed will block the bleeds causing severe fueling problems.