Cavitation problem with new engine
I have a Zodiac 2.85m dinghy, this model has a solid floor with an inflatable keel.
Previously my engine was a Mercury 6hp short stroke and it performed well, took a few seconds to get on the plane but would achieve about 14mph with 2 of us on board.
I replaced the engine this year with a Tohatsu 9.8 2-stroke short shaft, which weighs the same as the Mercury.
The engine initially seems to perform very well, but as soon as you open the throttle to get it on the plane it cavitates badly, the engine races and the boat loses speed.
I did get this very occasionally with the old engine, but it seems much worse now.
The anti-cavitation plate is about 2 inches below the bottom of the transom, the same as the old engine.
How can I stop the boat from doing this? The only adjustment is engine tilt angle which I have not tried yet.
I cannot imagine that I would need a long shaft engine with this small boat.