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Winterizing Must-Do’s

Gas, oil and battery need attention before the freeze hits

There’s lots to do to winterize your boat and motor, and lots of checklists online and at marine stores tell you how. Let me remind you of the steps that can be the most critical.
    Topping off your boat’s gas tanks and dosing with the correct amount of fuel stabilizer is first on the list of must-do’s. Seek out ethanol-free gasoline (E-0), as it is relatively stable during storage.
    Ethanol is an additive present in 90 percent of all gasoline sold in this country. E-10 contains 10 percent ethanol, and E-15 has 15 percent. Ethanol is mandated by the U.S. government to reduce our reliance on foreign energy sources. Modern marine motors are designed to run on all of the ethanol-added fuels, but problems can occur in extended storage.
    Gasoline itself can absorb a small amount of moisture. Ethanol can accumulate 50 to 60 times more, generally from condensation inside the fuel tank. When the ethanol accumulates too much moisture, phase separation occurs. The fuel separates into two distinct layers, a top layer of (now) low-octane gasoline and a bottom layer of water-rich ethanol. Neither of these is desirable in a modern outboard engine. Both can cause damage.
    If your motor will not start or it suddenly runs poorly, phase separation might be the cause. Do not try adding fresh gas, as it will not effectively mix with the separated fuel. Drain the tank and dispose of the spoiled gasoline at a hazardous waste site.
    The next most important step is changing the lower unit oil. The lower unit of an outboard contains the drive gears and prop shaft, rather like the transmission of an automobile. The gears are lubricated by thick 90-weight oil. It’s a good idea to change it every year.
    Winterizing is the best time, for two reasons. First, so you don’t forget to do it. Second, to be sure the prop shaft seals have retained their waterproof integrity. When drained oil has a white or milk-colored tone, your seals are failing and should be replaced.
    If you do not drain your oil and the engine is stored outside over winter, any water that has leaked into the lower unit will eventually separate from the oil and accumulate at the bottom. When temperatures drop below 32 degrees, that water will freeze. Expansion can crack the unit’s casing, disabling your engine and incurring a costly repair.
    Replacing the seals is not a difficult operation, and manuals and websites describe exactly how to do it. If you prefer to have a professional mechanic handle the operation, be sure that you do it over the winter while their workloads are at a minimum. If you wait for springtime, the busiest time of year for marine mechanics, you may wait weeks.
    The last must-do is to disconnect your engine’s battery. Optimally you should remove it from the boat, store it in a temperature-stable area and place it on a maintenance charger. At minimum, it should be completely disconnected.
    Most boat motors, bilge pumps and general electronics are sophisticated enough to include some monitoring devices that will continue to operate even if the unit is off. While drawing only a miniscule amount of power, they will drain the battery over time, then keep it drained. And you’ll need a new battery come spring.