engine wont start

Boat is a 1990 310 Sundancer with 4.7 Mercruiser blue water engines. Originally kept in freshwater year round just splashed her in the Chesapeake about 3 months ago (saltwater). I have only taken her on 3 cruises since I got her. On my last cruise the port engine cut it's self off and wouldn't...

First post - winter start up attempted yesterday and engine was slow to start...then I heard the loud , squealing of the serpentine belt & then smoke emitted out from somewhere ! I stopped before any damage was done , but almost started up...any ideas what it could be ? The belt was on tight by...