outboard Motor Mount
One problem common with outboard installations on sailboats is the motor coming out of the water as the boat pitches up and down. When the motor comes out of the water, the prop has no load and the motor overspeeds badly.
This is why people want long shaft motors for sailboats. I know it is hard not to use something you already have, but unless you sail on calm water, you will likely have problems with your short shaft outboard for the above reason.