Originally Posted by CJL
Just a squirt until the tell tale tastes fresh and you'll be fine.
Or, alternatively, simply follow the manufacturers flushing directions. Your tastebuds will probably thank you.
There are no major manufacturers motors which are freshwater only. They're all designed to do either fresh or salt (though, if you do exclusively fresh, you might want to look at changing out the zinc anodes for a more freshwater oriented material. Magnesium, was it?)
The E-Tecs are supposed to be self-winterizing, which would generally include fogging the head, and purging the cooling system of water. The water part won't be an issue for you (more to do with expansion as the liquid freezes), but the fogging will be.
You probably want to look into some fuel stabilizer as well (or get around that by either running the tank dry, or draining it.) 2 to 4 months is about the length of time it takes fuel to start going off.
Congrats on the boat, and enjoy;