98 23' Bayquest (V-hull with a slight tunnel) with Merc 200 W/jackplate. At times I notice that the motor RPM will increase like it was missing before and then decided to start hitting on all 6. This weekend we took a long drive in varying water condtions. Going out in smooth water it ran steady 42 at 5500 RPM. After the water roughed a bit, during a long run, the motor RPM jumped up to about 5900 and the speedometer dropped to about 33. The boat might have slowed slightly but I am sure it did not slow down that much. While still runing I jacked the motor up, down, trimmed up and down and could not get it to grab again. I could stop and start over and it would run steady 42 at 5500 for a bit then do the same thing (RPM jump up and speedometer drop). The speedometer pickup is on the leading edge of the lower unit on this motor. That is why I suspect cavitation since it is effecting the speedometer. Once before I was expiermenting with the jack plate and it overheated with it up a bit. Since then I always run with the jack plate all the way down.
I hope it is not a hull design issue that cant be easily solved with an anti cavitation plate. Any thoughts?
I hope it is not a hull design issue that cant be easily solved with an anti cavitation plate. Any thoughts?