Problems With a Non Winterizing Boat Motor

Fuel

• If a boat gas tank has not been filled with a proper stabilizer solution and topped off before winter, it can cause rust and scaling on the inside of the tank. Partially filled tanks without stabilizer will also accumulate enough moisture (condensation) to dilute the gas and travel through the fuel system, where water can trap inside the carburetor. Poor engine combustion, stalling and missing will result. Old gas that has been allowed to sit in the tank for 3 to 4 months will varnish and gum-up. Gum and varnish clogs delicate carburetor parts.

Cylinders

• If the spark plug or multiple plugs have not been removed to "fog" the inside of the cylinders, rust can build up, which causes excess friction on the piston rings upon initial start-up. Fog spray contains a lubricant that protects delicate metal surfaces against moisture-induced rust. Improper fogging, or no fogging, will cause premature scoring of the rings and valve guides upon start-up

Oil

• Oil that has not been changed before winterizing will have poor lubricating qualities upon start-up. Any water that has entered or condensed within the crankcase, will cause the oil to lose it lubricating properties and viscosity. Oil must always be changed, and the level checked before seasonal storage of the boat.

Battery

• Boats equipped with auxiliary batteries must have their water levels topped off and be trickle-charged occasionally, to maintain a standing peak voltage. Batteries allowed to sit flat with low levels and no charging maintenance will discharge and provide insufficient voltage upon starting. Cables which have not been cleaned and lubricated will oxidize and fail to complete a voltage circuit.

Lower Unit Oil

• If the lower unit oil has not been changed and water exists in the lower unit case because of condensation, the seals, gaskets and moving parts will suffer scale and rust deposition. Leaks that have gone undetected have the potential to drain the lower unit, which can cause a catastrophic transmission failure during a medium or fast surface run. Air can enter the lower unit as a result of a leak and cause an air lock in the oil passages, reducing sufficient oil pressure.

Propeller and Shaft

• Proper winterizing involves the inspection of the propeller, shaft and thrust bearing. Propeller blades that are bent or fractured will set up dangerous motor and boat vibrations. Slack or abnormal free-play in the propeller shaft points to a worn key-way, deformed key or a worn thrust bearing. Failure to inspect and repair the propeller can result in losing it or damaging the shaft bearings or transmission gears.

Water Pump Impeller

• The water pump impeller, on both the in-out drive and outboard, cannot be allowed to sit inside the engine during winter. When the rubber of the impeller is not allowed to flex or move, it becomes brittle and loses its profile. A deformed impeller will not seal correctly inside the pump housing, leading to cooling water starvation and overheating. Water pump impellers can break suddenly, due to brittleness and operating in a dry pump housing.

Manifolds and Bilges

• Wet exhaust manifolds that have not been drained on in-out and inboard engines, can allow trapped water to freeze, then expand. Such expansion and contraction can cause the manifold to crack. Bilge plugs must be removed to keep rain out of the bilge area, where mold and dry-rot can result from standing water.