Winterizing your boat for the majority of us is the most dreaded day of the year. Warm weather is gone and so starts the wait for spring temperatures so we can hit the water again next season. Take these protective measures to assure your boat will greet you with a happy face when warm weather welcomes you again in a few months.
Run a fogging solution through the boat engine while it is running to protect internal parts
Spray a protective anti-corrosion film on the external parts of engine
Drain the engine block and manifolds and fill the engine with anti-freeze
Drain the lower unit gear oil and refill with fresh oil (stern drives only)
Grease all external fillings on stern drives
Disconnect the battery / batteries and store somewhere warm
Cover your boat
Remove spark plugs and spray oil on cylinders, then replace spark plugs
Change engine oil and filter
Remove prop and grease prop shaft
Add fuel stabilizer to prevent condensation in gas tank (run engine briefly to flush stabilized gas through fuel injectors and carburetor)
Winterize fresh water system
Remove outdrive and grease U-Joint
*** The above winterizing tips are only a list of suggested things to do your boat that I've collected over the years. Each boat may vary as to what needs to be done to winterize it. For complete instructions please see your boat's owners manual or consult your boat mechanic.