85 hp performance

ctrain

Recruit
Joined
Jul 20, 2003
Messages
4
1989 Force 85 hp. Chunky 1977 17' Reinell.<br /><br />Hello Force owners,<br /><br />Back in action from last season. I took the boat out last friday, crossed my fingers and fired it up. The boat was stored in doors with old fuel. Half way through the winter I added some Seafoam to stabalize the fuel. Seems to run great, a little smokey but great.<br /><br />The boat was new to me last year so I installed a tach and temp guage. Of coarse the tach was the wrong part, and it took me 6 months to take it back and get the right one.<br /><br />I installed the new tach and got it working right. When I run at full throttle, the tach reads 4500 rpm, and the speedo reads 36mph. I should add that there was approx 460 lbs of people in the boat at the time. I remember last year with only 2 people in the boat, it only hit about 36 mph.<br /><br />Is this what I should expect, or do you guys think I could squeze a little more out of her.<br /><br />I assume the prop is stock, but I cant be sure. The manual says it takes a 17x13 prop. I looked at the prop, and the only thing I could see stamped on it is a 19.<br /><br />Maybe with fresh gas and less people I could get my RPM's up. I should also use a GPS to check speed.<br /><br />If I change prop to bring up the RPM's, does this mean I will lose a little speed, gain speed, is it better for the motor to run at higher RPMS?<br /><br />Thanks all,<br /><br />Cisco
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,788
Re: 85 hp performance

Your motor should run right about 4700-5000 rpm.<br /><br />You likely won't get much more out of you boat and motor.<br /><br />If you drop the pitch to increase rpm, the speed will be the same +/-, because the increased rpm will make up for the lower pitched prop.<br /><br />Reducing the pitch by 2" from what you have now, should put you right at 5000 rpm.
 
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