Re: Is 5500 rpm top on a 85hp force
This one runs 5900 with a 21 pitch prop. No, you won't lunch the engine. They are short stroke engines with no valves to float. They are probably capable of 8000 or more, but of course, over 6000, you are out of the power band.
This boat is a 14 foot flat bottom. Your 85 will probably not turn 6000 with a 21 pitch prop, more like 5000, and speed should be up around 50--depending upon how fast the Vandal hull is. Start with the cavitation plate about one inch above the vee and use a cupped prop. Use the bottom holes so you can lower the engine if it cavitates excessively, however, my experience is that these engines will run one inch high.
If it is a really fast hull, be expecting chine walking unless the hull has a bottom design to prevent this. Carry at least 9 gallons of fuel because you will be running full throttle all the time and you will be able to watch the level go down. I carry 15 gal in this 14 footer.
At these speeds in this size boat, a "man- overboard" or "Dead Man's" engine kill switch is a MUST, and wear your life jacket AT ALL TIMES. This photo was taken in october and the jacket is under the sweatshirt.
Oh, yeah! Here are a couple of photos of transom reinforcement with .080 aircraft aluminum to handle the power.
