Ok. I'm working on a Kawasaki FB 460 / 12.5 HP (single cylinder). I'm trying to make sure the valves are set properly. The manual says that the valve width gap should be between .0039 - .006. Am I understanding this right? At top dead there should be a gap in the seating of the valve??? I thought that at TDC the valves should be completely seated and shut. Isn't that how a combustion chamber gets max power? Someone please tell me if I'm wrong here. The engine won't start, sputs and backfires through the carb and muffler and sure acts like there's a valve issue. Everything else is in spec on this engine. I've put in new valves in and lapped the valve seats. Everything looks good except this valve seating issue. Is this true? Should there really be a gap in the valve and valve seat at TDC of between .0039 and .006? Or should the valves be completely sealing the combustion chamber? Thanks guys.