3 steps to prep your boat engines for winter—the right way

Published: October 26, 2020

boat with outboard engine Alberto Masnovo/Shutterstock

Small, sub-10 hp boat engines are frequently subject to shoddy maintenance, especially at cottage closing time. Bad fuel left to gum up the carburetors during winter storage is the “number one problem,” says Brendan Keys, the general manager of GA Checkpoint in B.C.’s Lower Mainland.

“Too many people still cling to the old boater’s tale that says to drain the engine, you simply run the boat engine until it runs out of gas and dies.” This strategy leaves gas in the fuel bowl, where it will oxidize, leaving deposits and causing grief when you return in the spring.

At his own cottage in the Cariboo region, Keys begins the outboard winterization process early. Ethanol-blend fuels will go bad in as little as three weeks, he says, so it’s best to add fuel stabilizer at the end of the summer, when you start using the outboard less frequently. Keys insists that most cottagers have the tools and skills to perform a complete small-engine winterization on their boat engines. 

1. First, drain the gear oil from the lower unit—collecting the used oil and inspecting it for water and metal filings (in both cases, it means your engine needs to go to an expert)—and replace it with fresh oil.

2. Second, change the engine oil on four-stroke motors. (In the case of some two-strokes, you should run the engine and spray fogging oil into the intake valves—check your owner’s manual for more details.)

3. Third, completely drain the gasoline by disconnecting the fuel line and opening the drain plug in the bottom of the carburetor. Finally, in saltwater environments, Keys recommends that you apply silicone spray under the engine’s hood and treat any grease nipples with marine lubricant to prevent corrosion.

This story was originally published in the Fall 2017 issue of Cottage Life. 

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