Here in northern Illinois, the boating season ends fast. One warm weekend in late September, then suddenly it's 40 degrees. A boat that sits five or six months needs a bit of prep, and doing it in the right order saves you trouble in the spring.
Always check your engine maker's storage procedure first. Outboards, sterndrives and inboards differ, and so do carbureted and fuel-injected engines. This list covers the common ground.
1. Treat the fuel first
Today's ethanol-blended fuel can absorb moisture and break down over a long layup, which gums up fuel systems. Fill the tank most of the way to leave less room for condensation, and add a fuel stabilizer at the dose on the bottle. Then run the engine long enough for the treated fuel to reach the whole fuel system. Stabilizer sitting only in the tank doesn't protect the engine.
2. Change the engine oil while it's warm
Used oil holds acids and moisture from combustion. Leaving it in the engine all winter lets those sit on internal parts. Change the oil and filter right after that run, while the oil is warm and drains well. Use an oil that meets your engine's rating; AMSOIL makes marine engine oils for four-stroke and two-stroke outboards and inboards.
3. Change the gear lube and look at the old oil
Drain the lower unit (or sterndrive) gear lube and look at it:
- Clean and dark: normal.
- Milky or creamy: water is getting in, usually past a seal. Have it fixed before spring, because water left in a gearcase can freeze and do real damage.
Refill from the bottom drain hole up until it comes out the top vent hole, with a marine gear lube that meets your engine's specification.
4. Fog the engine (if your manual says to)
Fogging oil coats the inside of the cylinders to keep rust off over the winter. Many carbureted engines call for it; some fuel-injected engines have their own procedure or don't need it. Follow the manual.
5. Drain water that could freeze
Inboards and sterndrives with water in the engine block or manifolds must be drained, or winterized with antifreeze per the manual. Freeze damage to a block is the expensive mistake.
6. Grease and protect
- Grease the steering, tilt and other fittings with a water-resistant marine grease.
- Disconnect the battery, or put it on a maintainer.
- Clean the boat, open the storage compartments a little so they don't trap moisture, and cover it well.
Come spring
Do a quick check before the first launch: battery, fuel lines, belts and the gear lube level. If you put it away properly, spring is mostly just reconnecting the battery.
Not sure which oil or gear lube your outboard takes? Try the outboard lookup, or send me the make, model and horsepower.
Questions about your vehicle or equipment?
Send Byron the year, make and model and he'll point you to the right products.