Prop mismatch with cavitation

[LastBoat]

I have a 1992 Seaswirl Striper sold with a 120 Johnson. Two cycle engines banned on lake and decided to repower with 115 hp Yamaha rather buy a new boat. Boat weighs 1850 lbs without engine.
I cannot drop the stick without the prop spining, I cannot pull a coke bottle off the dock much less a skier out of the water. If I goose the engine I can get up to speed and plane.
Prop is 13 x 19-K not stainless. Dealer help is useless. I wish I had the stats on my Johnson prop as a starting point.
Any suggestions

 

[Tig]

Re: Prop mismatch with cavitation

Welcome to Iboats, Lastboat.
Read the sticky at the top of the prop forum and get us the information listed. Once you post that, the prop experts will be able to understand exactly what's going on.
What exactly did the dealer say about this?

 

[musky49]

Re: Prop mismatch with cavitation

You need a different prop, I have experience with that exact prop. It is an uncupped cleaver style prop, mine slipped around 19% at wot. With that heavy of a boat I'm guessing a 13.25x 17 cupped prop will do the trick.