I accidently found the power problem on same motor while running at the ramp it in gear with the cowling off I reached up and placed my right hand at the top starboard side to look at the fuel pressure. Motor suddenly picked up over 1000rpm. The motor wiring harness was bad. Replaced it and motor ran like a stripped ape. Have seen this on XRI motors 4 times.
“The world will not be destroyed by those who do evil, but by those who watch them without doing anything” GOD IS GOOD