447 or 503
Is there another way to identify what model I have? This Rotax has a 4 blade prop, which says its for a 503. However it won't reach the needed RPM's. Went to a lower pitch block, it won't move the wheel on the plane. If its a 447 then the prop is too large. There has to be away to identify the model of this engine without pulling the engine off and tear it apart. Need this info so the correct prop will fit. There are no records kept on this engine. Engine run good, just can't swing a large prop.