[bitsamonkey]

I would fix the overheat problem and take it out again. After a long lay-up you can have stuck rings or rusty valves and valve seats that aren't seating properly. Both of these things can "fix themselves" by just using the boat. Just make sure you know why it overheated in the first place, fix that and then keep an eye on the coolant if freshwater cooled or look for excessive steam coming out of the exhaust. I doubt you damaged that motor by overheating it a little.