4800 at wot 85 force

[learning]

I have a 85 force and the compression is 110 in 2 cylinders and 100 in 1 cylinder. At wot im at 4800 rpm's at 28-30 mph, other people with this motor and the 50 force are saying their closer to 40-45 mph. Is it time to rebuild it or does the prop have anything to do with it or could it be something else. By the way it is a 1985 16ft bayliner capri, my very first boat i've had it 3 months please no bashing. Any information would be very appreciated. (still learning)

 

[JB]

Re: 4800 at wot 85 force

Howdy, Learning.<br /><br />Okay, I wont bash.<br /><br />Your compression is fine, your WOT rpm is low.<br /><br />Give us some history here. Did it ever do any better for you? <br /><br />This could be an engine problem, but I don't think so. I think it is a boat or a prop problem.<br /><br />Your friends' speeds are like the fish they catch. Ignore them.<br /><br />If your boat has been this way since you've had it, check the pitch on your prop and the weight of your boat. One thing that could be wrong is too much prop for the weight.<br /><br />12Footer is our B'liner Capri powered by Force Expert. He should be along as soon as the Bass quit biting. <br /><br />Let us know your prop pitch.

 

[learning]

Re: 4800 at wot 85 force

This has been the speed of the boat since ive had it. The only number i saw on the prop is 523 17. I heard of the hydro foil i think thats what it is called, would that help in any way. P.S. we are trying to learn to water ski and would the foil help plane the boat quicker and does that make a difference when trying to ski. Thanx.

 

[sony2001]

Re: 4800 at wot 85 force

learner, being in the 4800 rpm range is very good BUT the weakest link in the combination of prop, rpm, and compression is the last. New it was 150 to 165 psi and running 110 on a Force is definately on the low side. I would do at least a decarb per month to raise it somewhat. Your tach will tell you if its working. "Mercury Power Tuner" can't be beat!