cant seem to get over 5250 rpm's. switched from a 19p to a 17p and rpm's stay the same,just 6-7 mph slower. it hits 5250 and starts to fall off down to 5000 and it may or may not climb back. you can back the throttle off a ways and it doesnt change rpm's. it seems rich on top to me,plugs pretty black-put new plugs in and no change. Removed cowling and tried it, rpm's didnt drop from 5250.put cover on and they dropped again. Also noticed the throttle plate only opens about 3/4 at wide open. Is this normal? It has done this since new,but figured it was my prop. Any advice?
