Prop wind-up

[DBFRANK]

I think I am encountering prop wind-up...as when I am at top RPM, they slowly go down. Engine operation seams fine, but loose RPMs over a distance of 500-600 yds. when pushing load. With nothing in boat, doesn't seam to do this unless in strong current. Had prop rehubed several years back and they used wrong hub...fit ok on 2/3s of shaft, beat rest of the way on with rubber mallet. After spinning that hub out in mud over a period of seasons, sent prop to manuf. who then told me it was the wrong hub and they rehubbed correctly. Of course local prop shop long gone by that time! Since hubbed correctly, I have encountered this problem. Did I smash the gear bushing that goes on shaft before prop?? or/and did I smash washer spacers after prop before nut??...and would a few thousandths diff. in that area cause what I am encountering?

[boats.net]

Mark a line across prop and prop thrust washer to see if prop hub is slipping, run it and recheck line to see if mark is still aligned.