I think Roger Long could be on to something. I had a like experience
with my Hawk XP. Although it has a different engine than the "R", I
too had a power loss. Airplane would not get off the ground well and
climbed poorly. Flew a little slower, but not seemingly much. Had
the fuel system overhauled as well as the governor. No change.
Leaning had no effect. Compressions were no lower than 73. After a
couple shops, the mechanic found same issue Roger mentioned. Mechanic
replaced a few parts and the old plane was back. Good luck!


Mark