Offshoreonly.com - WINTERIZING

Here's my full list... I have my marina service my drives, but I do everything else... I have Merc 525EFI's which are closed cooling.

 Add Fuel Stabilizer to gas tanks
 Unbolt one engine hatch (in case you want to get in over the winter and batteries have been removed)
 Clean bilge
 Remove batteries
 Remove propellers
 Remove all electronics
 Coat trim tabs with corrosion inhibitor
 Coat steering system with corrosion inhibitor
 Bounce sheets in engine compartment
 Damp-Rid Bag in engine compartment
 Drain fresh water tank
 Add antifreeze to fresh water tank
 Run antifreeze to galley and head sinks and transom shower
 Add sanitizer and antifreeze to vacu-flush holding tank through toilet
 Clean refrigerator and prop open
 Remove pillows, fenders, safety equipment and supplies from cabinets and head
 Hang Damp-Rid bag in cabin
 Hang Damp-Rid bag in head
 Bounce dryer sheets in cabin
 Remove fenders, supplies from side compartments in cockpit
 Remove tools from under bench seat
 Hang Damp-Rid bag in cockpit
 Remove cockpit carpeting
 Bounce dryer sheets in cockpit

For each engine:

 Check spark plugs for signs of any issues (good to know before next spring)
 Flush raw water cooling system (run each engine on freshwater for 15 minutes)
 Change oil and oil filters
 Fog engine on fuel / oil / gas stabilizer mixture
 Drain headers and cooling system components of all water
 Run engine again with anti-freeze through raw water cooling system while on gasoline / oil mixture
 Drain headers, leave drains open
 Drain sea water lines between strainers and drives
 Blow out sea strainer lines
 Drain gas tank / add stabilizer for whatever's left..
 Coat engines with corrosion inhibitor
 Fill sea strainers with antifreeze
 Cover exhaust tips to prevent rodents making a winter home..

There are differing opinions on whether you should store your boat with full or empty gas tanks. Several marine surveyors have told me that if the gas in your boat contains ethanol, you want as much out of the boat as you can as no matter how much stabilizer you put in, you cannot stop the absorption of water and the lower the fuel level, the better. So, I am draining my tanks. To do this, I bought a small 12V fuel pump, wired it to battery clamps and a switch, and then put a 3/8" NPT male adaptor on the inlet hose that I will attach to an output port on the fuel/water filter base and the output hose I will run into a whole bunch of gas cans..