prop free wheeling?

[sprintex]

Ok on my new to me 85 16' Hobbie power skiff with an 88 60HP Mercury with power trim and a Doel-Fin. When I give it gas to get up on plane ( trim all the way down) all I get are RPM's it is like the prop is not digging in. At first if I gave it gas slowly I could get up on plane, yesterday I could not get over 2500 with out it spinning. It was so bad I thought I would need a tow back but after backing off the gas it finally caught and I got back to my slip.
So could it be a bad prop hub? That when you get enough power the prop slips?
Thanks

 

[Yepblaze]

Re: prop free wheeling?

It could be a slipping prop "hub" that can be tested with a dab of nail polish on the prop and one on the nut. If after a brief run the nut and prop dots still line up the hub has not slipped.

It's also possible that it just cavitates when trimmed in all the way, in which case, try trimming it out some.

There are other possibilities such as shaft length compared to transom height. And or something causing turbulence to enter the prop.

 

[sprintex]

Re: prop free wheeling?

Thanks for the paint dot idea. Already played with the trim.