Take the cover off(the one with 4 screws) and be sure the inlet needle lever is not sticking up too far--it should be flush with the casting right next to it..Also the gasket goes on first, then the diaphragm...If it still runs rich, try closing the high needle completely, then lean out the low needle..They should both be open smoewhere around 1 and 1/2 turns from closed..There is no exact setting, so experiment....