Winterizing your Four-Stroke Outboard

Modern four-strokes need a little TLC

By Mike Gridley

Over the years, I’ve observed that many boaters take their outboards for granted when it comes to winter or extended storage. They just let them run them dry of fuel, let the water drain out, and leave them on the boat or store them in the basement. Well, maybe your old 9.9 two-stroke survived that but modern four-strokes need a little more attention, so here are the steps required to properly store an outboard.

If your boat has an internal tank, ensure it is full to prevent moisture buildup and treat the fuel with a storage stabilizer that also has additive so ethanol fuel will not break down or phase separate. Two good fuel treatments for this are Sta-Bil Marine fuel treatment and Star-tron.

To get started, the engine must be warm. Make sure there is a good flow of water from a set of muffs when doing this. After warming the engine, the first task is to drain the old oil. For this, the best approach is to use an oil extractor. With the oil drained, the next step is to change the oil filter. Before installing the new filter, coat the filter’s O-ring seal with oil so it seals properly.

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View the video online: See Episode 11 of the 2010 season of PowerBoat Television.