Whats happing to my prop

[mrcrabs]

My 1975 Johnson 70 13 3/4 17 prop on a 16ft trihull has been devoloping this abrasion spot over the last 2 seasons, I have had a few dings and tapped them out and over all the prop looks good and symmetrical but seems to vibarate at low idle, I don't have tilt & trim so I run it in the middle hole. I just did a tuneup on the fuel system and installed boyesen reeds then tuned the engine at the marina this weekend, I'm getting just about 5200 rpm according to my tach and I have seen it do better. Whats happening to my prop and what would a suggestion be for a new one? maybe a turning point cupped 15 pitch?

 

[Bob_VT]

Re: Whats happing to my prop

It is where the water and bubbles boiled away the paint. Very common in aluminum props.

 

[1kruzer1]

Re: Whats happing to my prop

I would definitely change to a 15 pitch prop to get the RPM's up a bit. I have the same motor in a 1976, and recently changed from a 17 pitch to a 15 pitch Solas Rubex aluminum 3 blade.. I can't speak about the Turning Point prop, as I've never owned one, but I can and do recommend the Solas. Very impressive and inexpensive prop.