A few years ago I got tired of paying a mechanic to winterize and shrink wrap my boat so i signed up for an outboard engine mechanic's course and have been doing all the work on my engines since and found out just how easy it is to winterize an outboard engine. Here are the steps if you want to save yourself a little cash...
1. Fill up your gas tank
2. treat with Stabil and Enzyme treatment
3. run boat to get treated gas into engine
4. run boat on land at idle speed for fogging
5. Spray fogging oil into engine carb or fogging hole (4-stroeks) until engine dies or almost dies out.
6. Remove spark plug and give about a 3 second spay with fogging oil into each cylinder head.
7 replace spark plugs, only hand tighten (do not reattach plug wires)
8 turn over engine 3 cranks
9 replace plug wires
10. remove lower unit oil (works like on a vacuum - undo bottom first and then top)
11. refill lower unit oil and replace gaskets on screws
12. remove cotter pin, bolt and prop
13. grease prop shaft and cover to protect from weather
14 pump antifreeze into your engine either with muffs or through the hose clamp (newer engines). Use hand pump, don't start engine to circulate fluid.
15. Run antifreeze through all pumps - bilge to live wells to macerators.
16. Charge, remove and store batteries where they will not freeze
Shrink wrap...you're done!