Boat plumbing is a lot easier for the do-it yourselfer than plumbing at home, mainly because it doesn't involve rigid pipes running inside solid walls.
A bilge blower is important not only because the USCG may require it, but also because your life may depend on it. Venting your bilge of potentially lethal gas fumes is no job for a jury rig.
Heat Exchanger Maintenance
When did you last replace the zinc pencil inside your engine's heat exchanger?
Off Season Storage for Outboards
Take extra care to make sure that your engine is properly protected, especially when storing. You'll need fuel conditioner, grease, gearbox lubricant, and storage fogging oil.