I am looking at a 2000 21 foot walk around with a 4.3 liter Volvo motor with 70 hours. It has a carburetor, not fuel injection. The boat has been out of the water since last season. The boat yard says it was properly winterized Fogged etc. My question is what to look for when checking the engine, and how long will the motor stay winterized? I have only had out boards on previous boats. The motor comes with an extended warranty till 2005. Any suggestions would be greatly appreciated.