With my 46FX engine with an APC 11-5 prop I adjust for max rpm and then richen by 3 clicks. This consistantly gets me 14,200 rpm. If I get less, then somethings wrong. Funny thing is with my 40FX with an APC 105 prop I also get 14,200 rpm on that engine. I don't know if its different at other elevations or not but thats what I get at my location. When I read about how other flyers like their engines because "it screams" doesn't mean anything to me. Tell me how many rpm you are getting and what prop you are using then I might be impressed![8D]