1987 mercury 9.9 outboard drive problem?

Question

I have a 1987 mercury 9.9 outboard on a 12' boat. As I was towing my not-so-good sailor/daughter's sailboat to shore with it, I increased throttle speed a bit and the engine revved high with no power to the propeller. Got it to shore OK after that at lower speed. Next time I used it the engine started & ran fine, reverse worked fine but at above 1/3 throttle I get high revs but no power to the prop again. Below one third throttle the prop can push the boat. The lower housing grease seems fine (except for some red spots in it and the prop did not seem loose when I pulled on it by hand.Have not put a wrench to the prop yet. Thanks

Answer 1

Sounds like you have spun the hub in the prop.  Have it rehubbed, or buy a rebuilt prop, about the same price for a small prop.

Answer 2

I agree with jims it sounds like the classic spun hub, but comeback with a new question if the prop shop determines that the prop is ok.  Include the model year of your engine.I've only seen one prop hub spun by towing something heavy. I'm thinking you hit something. Good Luck!