Boat Winterization Tips

Winterizing your boat check list


Fuel Treatment

Treat your boat's fuel with a stabilizer. After adding it to the fuel, run the engine for 10 minutes or so to be sure stabilized fuel circulates throughout the engine. If you don't stabilize the fuel, carburetors and fuel injectors can be clogged with varnish deposits that ruin fuel systems. Cost if you do: $5 to $10. Cost if you don't: $250 to $1,200.

Fog the Engine Cylinders

Aerosol fogging solutions coat the inside of the engine to protect it until spring. Each engine manufacturer makes proprietary products they promote as ideal for their engines. If you don't fog the engine cylinders, corrosion can form inside the engine, covering the cylinders, pistons and rings with a patina of abrasive crud. Cost if you do: $5 to $15. Cost if you don't: $2,500 to $10,000 (or more).

Drain systems

(for inboards and outboards) 4 stroke inboards: (ie 350 Chevy): Locate and open the petcocks (some engines have bronze plugs similar to bilge plugs) underneath the manifolds and on the sides of the engine block. Remove the water-pump hose from the bottom of the water pump to let it drain completely. If you don't drain the engine, water in the cooling chambers can freeze, expand and crack the engine block and manifolds. For inboard two stroke motors like Mercury Sportjet units, the engines self drain. Some have a winter draindown plug that should be removed. If equipped with a sand trap, drain the water from the sandtrap by removing the clear bowl. Any water cooled heater units should have the lower hose T removed and it is a good idea to blow air through the hoses to rid water from the heater core. Change the oil in the jet unit and gearbox in the event any water is those cavities. Never leave these cavities empty over the winter to prevent condensation.

Outboards self-drain. Drain and refill the lower unit of outboards w hi viscosity lower unit oil. Clear, amber-colored lubricant means your gear-case seals are in good shape. Milky and sometimes lumpy oil means the seals need to be replaced. Grease the jet unit of outboard jet units to expel water and existing grease until new grease appears. Cost if you do: $0. Cost if you don't: $5,000 to $20,000.

Change the Oil

Inboard 4 strokes: Change the engine oil to eliminate moisture and prevent corrosion. If you don't, moisture can cause excessive wear, which can lead to loss of power, poor fuel economy and possible engine failure. ON both inboards and outboards, change your oil and fuel filters annually, either in the fall or spring. Cost if you do: $30 to $150. Cost if you don't: $500 (in extra fuel) to $10,000 (engine failure).


Boat storage

If you are storing the boat outdoors over winter, remove the battery and put it indoors on a battery tender or trickle charger. Remove any canvas and store indoors if possible or somewhere it cannot be handled in extreme cold to prevent fabric cracking. Remove the drain plugs and store the boat with the nose of the boat slightly elevated. Put a foam block or sawhorse under the l tongue so that the weight of the boat is not relying on the trailer tongue jack, as the weight of snow can damage the jack. Remove snowloads over the winter to prevent windshield damage or construct a simple support system to keep snow and debris out of the boat over the winter. (2 x 4’s, plywood, etc)