For the engine:
http://www.boatsafe.com/nauticalknowhow/winteriz.htmBoatSafe.com wrote:Outboard Engine(s) - Flush engine with fresh water using flush muffs or similar device attached to the raw water pickup. Let all water drain from the engine. Wash engine down with soap and water and rinse thoroughly. Disconnect fuel hose and run engine until it stops. It is important to follow a step by step process to make sure that all fuel is drained from the carburetor to prevent build-up of deposits from evaporated fuel. Use fogging oil in the cylinders to lubricate the cylinder walls and pistons. Apply water resistant grease to propeller shaft and threads. Change the gear oil in the lower unit. Lightly lubricate the exterior of the engine or polish with a good wax.
Fuel - Fill your fuel tank(s) to avoid a build up of condensation over the winter months. Add a fuel stabilizer by following the instructions on the product. Change the fuel filter(s) and water separator(s).
I'll put some stabilizer in the gas and disconnect the hose to the tank and let the engine run out of fuel. I'll simply empty my 6 gallon tanks. I'll put some mouse poison inside the boat.
I'll put one of these inside West Marine:

Anything I'm missing? My engine has EFI. Is it worthwhile to put the trailer on a jackstands to take pressure off the tires? Is it best to wait till Spring to change the engine oil?
