power loss

I just purchased a 1991 Pro Line boat with a 1991 Yamaha 115 hp motor that has an accelleration problem. When the boat is out of the water and connected to a water hose, it runs fine. I can put it in forward gear and throttle up the rpms with no problem. However, when the boat is in the water it will lose power and die every time I put it in forward and attempt to accellerate. I have checked the fuel filter and cleaned the carburetor. Is there a governor connection or anything else that I can check?

Thanks for any help. lkh

Thank you. I'll give it a try.

Thanks Redfisher,
I finally got time to take the carbs off and clean them. You were right.

Thanks again,
lkh