I just went thru this with my Beech Sundowner. It was not making
minimum static rpm and would not go over 2500 at 7500 ft leaned.
Everything checked out, then pulled the prop and had the prop shop
check it and it failed. Not enough metal to overhaul it and it
surprised me cause it looked good.

Put a new prop on it and now getting 125 rpm more at static.


Bob Fry wrote:
Aircoupe Alon A2 with C90 engine with two props, one 48" pitch and the
other 52". It doesn't make the static runup RPM minimums with either
one, for instance the 48" prop should be 2225 to 2325 rpm, I averaged
out to 2162 rpm. Likewise the 52" prop falls short 100 rpm or more.

Three years ago when I checked the tachometer, it read a little
slow--maybe 10-20 rpm at speed, that is it would indicate 2300 and the
electronically measured rpm would be 2310 or so. Assuming that's
still true, what would cause the engine to not make minimum rpm?
Where should I start troubleshooting?