85 force and pontoons

[myerkes]

I have a 1988 85 Force OB that runs well. I have it on a 20ft pontoon boat and here is my problem. Since installation on this boat I have never been able to get into proper top end operating range. The cables are all properly adjusted, prop has been pitched down to 11 pitch and still I cant get above 4200 rpm. According to the manual I should be able to get well into the 5's<br />I need to get a hold of the technical output info for this motor to learn how much HP the motor is producing at 4200 rpm. I have been considering replacement with a smaller 4stroke and cant come up with any intelligence from the boat manufacturer. " more hp should help it go faster" which is dumb considering it is a displacement not a planing hull. Any help will be appreciated

 

[DJ]

Re: 85 force and pontoons

myerkes,<br /><br />I dont't think more hp. is going to help your speed. Toons get to a point that nothing will push them any faster. I also don't believe that you are going to find a prop with less than 11" pitch for that engine.<br /><br />Are you sure your tach. is right. On a pontoon, the prop slippage is usually quite high.