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You've had a blast on the boat with family and friends all summer, but now it's time for all that water fun to end. If you want to repeat the good times next year and protect your engine during the cold winter months — thus minimizing early season startup problems — read on.
Note: This how-to features an inboard 1999 Bayliner 2050ss Capri stored in Northwest Arkansas, a freshwater environment where the winters rarely get below -10 F. For colder climates, the process is similar, but should incorporate an antifreeze that can stand up to the typical winter temps there.
Consider this a general overview of the process. Every boat is slightly different, every climate has unique requirements and saltwater and freshwater situations require different steps.
Motor flusher engine muffs
Thin piece of wire
Boat cleaner (any multi-purpose cleaner will work)
Fill the tank with gas to prevent air (and therefore condensation).
Condensation equals water, which you don’t want in your fuel come spring.
Yoon Kim for Family Handyman
Run the Boat
Run the boat on dry land, following your typical procedure. Find the water intake, located on the stern drive. Place muffs over it and run water into the inlet via a garden hose, which will prevent overheating. Start the engine and allow it to reach operating temperature. Here’s a good tutorial if this is a new process for you.
Run the boat for as long as it takes for the gauges to reach normal operating temperature, typically around 15 minutes.
This opens the thermostat to allow antifreeze to circulate through the engine.
Yoon Kim for Family Handyman
Fog the Engine (optional)
Many people don’t do this, or don’t do it every year, though it protects the cylinders and carburetor from corroding and isn’t difficult.
While the engine is hot, spray fogging oil into the carburetor until the engine dies.
The oil will suffocate the engine while coating the carburetor and cylinders in a thin layer of oil.
We used STA-BIL Fogging Oil, which has a good reputation. There are plenty of other brands on the market.
Every boat battery terminal is a bit different, but we used an 8-mm. wrench on ours.
Label the positive and negative wires with a piece of tape and a Sharpie for easy re-install in the spring.
Bring the battery inside to a covered, ideally climate-controlled space, and plug it into a charger.
Winterize the Trailer
There’s not a ton to winterize on the trailer, but it’s still important. Moving a boat from a neglected trailer is not a fun task. (Trust us — we’ve done this with a jet ski, which was difficult enough!)
Top off boat fuel.
A full tank will mean additional weight on your tires and will give you a better gauge of tire pressure.
Note that each gallon weighs about six pounds.
Fill up tires with air, with your air compressor or at the gas station.
Every tire is different so refer to the tire’s sidewall. Do not exceed the maximum pressure rating.
Inspect trailer and bearings for rust and corrosion.
Address these issues now before your trailer and boat are parked for the winter.