86 yamaha 50ELJ slipping??

[kbert1171]

I was heading back to the launch today and had it full throttle, as most lakes we fish are no wake and I wanted to check top speed.
Anyway, we were cruising along and the motor began over-reving, so I backed it down immediately to idle. It was running fine, water impeller working well, and full of oil. It was still moving us along, but when I gave it some throttle, and not much, it began over-revving again. It was like a clutch slipping in a car. Fine until you gave it some throttle, and then revved way up again.
Any ideas what is going on with it? I'm completely baffled.

 

[robert graham]

Sounds like the rubber hub bushing inside the prop has failed….can buy a new prop or have your rubber hub bushing replaced at a propeller shop..If there’s one near you.

 

[99yam40]

I also say it is a spun hub.
if you want to prove that,
mark the hub and prop
run the motor to cause the problem and then inspect the marks to see if that are not aligned anymore