excess cavitation (or maybe any is excessive..)

[disisjc]

Hi,
I just bought a used 24 ft with a 88 hp Johnson...It runs very well til it seems like about half throttle it starts to cavitate really bad..Looks like someone has rebuilt the transom if that helps. Don't enough about pontoon boats to ask the right questions, so any suggestions as to what I can do to fix would be appreciated...Thanks in advance for your replies..

 

[lncoop]

Re: excess cavitation (or maybe any is excessive..)

Could be ventilation, but my money's on a spun hub. Do you know how to check for that?

 

[coastalrichard]

Re: excess cavitation (or maybe any is excessive..)

You mention possible transom work. When the motor is down in running position, is the cavitation plate level with the keel?

 

[MH Hawker]

Re: excess cavitation (or maybe any is excessive..)

On a toon you have to look at it while running, but a picture of the transom would help. but unless it is real high I would also guess a spun prop.

 

[disisjc]

Re: excess cavitation (or maybe any is excessive..)

will try to get some pictures this weekend and post them..

 

[EricJRW]

Re: excess cavitation (or maybe any is excessive..)

Why do you think cavitation instead of ventilation? Also, what speed and RPMs are you at?

FYI, I would loose speed at higher RPMs and my problem was a spun hub. To make a looong story short (it's probably still here if you search) I bought a new prop (one without a rubber bushing) and had the old prop repaired to use as a spare.

PS. Pictures are always good.