I got a 1969 25 hp Johnson 25r69. Heading to the ramp the other day and the thing started slipping during the acceleration like a spun prop. You had to let it get back to idle before it would pick up again. The funny thing is that this prop works with the old shear pins, I can't see how it is possibly spun and the shear pin is intact.
I got it back home and drained the foot oil and checked for shavings, none. Then i took the gear housing off and everything looked good no worn parts. Next i took the drive shaft out and both ends look fine, no wear. What the heck is going on?