Re: Just how fast...
As stated above, 30-32 MPH is about right for an 85 Force on a 19 foot hull. Oh, you can play around a bit and, possibly squeek a bit more out, but basically you are there.
Please do not try to "Tune" the engine before you go over to the Force forum and search and read my post: Synchronizing carbs and timing. There is a real danger of damaging the engine to the point of needing a rebuild with improper settings.
Back to speed: A tach is absolutely necessary. Once you know that the engine is running at its rated RPM at full throttle, then you know the prop is correct. Once you know you have the correct prop, you take the prop pitch, gear ratio, and engine RPM to figure THEORETICAL top speed. Subtract about 10 % for estimated slip and this is the top speed you would expect. In most cases, the Force engine will not reach this expectation but fall a bit short.---It's not a bad engine, if fact in many ways it is a good engine to own. It is just that it is a very old design dating back about 50 years and as such, its ability is limited compared with other name brand engines of newer design. However, at the end of its market life, Mercury had started to make improvements which did increase performance in the post 1994 models.
