There’s nothing like carving across glassy water on a summer day. But when winter rolls in, it’s time to put your jet ski to bed. Skip the prep, and you might find a cracked engine come spring. Let’s get it done right.
Give It a Deep Clean Before Storing
You might be tempted to skip the wash and just pull the cover on, but trust me, that’s a mistake. Dirt, salt, sand, and lake grime aren’t just ugly; they’re corrosive. Leaving that residue on your hull or trapped in the crevices all winter is an open invitation for mold, mildew, and oxidation.
- Wash thoroughly: Use a marine-grade soap to clean the entire hull, top deck, and seat. Pay special attention to the footwells and intake grate.
- Remove barnacles and debris: If you ride in salt or brackish water, flush the cooling system with fresh water for a few minutes while the engine is running (if still possible) to clear out any salt deposits that could crystallize and cause damage.
- Wax the hull: Applying a layer of high-quality marine wax isn’t just about looking good. It adds a protective barrier against moisture and minor scratches that can occur while the craft is in storage.
- Dry completely: Before you put the cover on, make sure every surface is bone dry. Trapped moisture is the number one cause of mildew on seats and mold in storage compartments.
Choosing the Right Storage Location
Where you store your watercraft matters as much as how you prep it. For many owners, renting a unit becomes the backbone of year-round jet ski storage, protecting the machine from moisture, rodents, and temperature swings. A little planning with your storage setup ensures your jet ski stays safe all winter long.
- Indoor units: Climate-controlled is ideal, as stable temperatures prevent condensation and mildew. Leave the seat slightly unlatched for airflow.
- Outdoor yards: Use a heavy-duty, UV-resistant cover. Park the trailer on plywood to block ground moisture, and invest in a good hitch lock.
- Rodent proofing: Storage facilities attract mice. Stuff steel wool into the intake and exhaust, and place peppermint oil or dryer sheets in compartments.
- Stay organized: Keep life jackets and gear in the unit so everything is ready to go when spring arrives.
The Engine: The Heart of Ski Storage
If there’s one area where you don’t want to cut corners, it’s the engine. Water left inside the engine block or intercooler is a ticking time bomb during winter. When water freezes, it expands, and that expansion can crack your engine block like an eggshell.
- Run the engine (briefly) to fog it: If you can still get the craft in the water or hooked up to a garden hose, run the engine and spray “fogging oil” into the air intake until the engine stalls. This coats the internal cylinders with a thick layer of oil, preventing rust from forming on the cylinder walls during the months of inactivity.
- Change the oil and filter: Old oil contains contaminants and acids that can eat away at internal engine seals over the winter. Always change the oil before storing, not after.
- Stabilize the fuel: Fill the gas tank to about 95% full to prevent condensation from forming inside the tank (which leads to water in the gas). Add a high-quality fuel stabilizer to the tank and run the engine for 5–10 minutes to ensure the treated fuel circulates through the entire fuel system and injectors.
Don’t Forget the Battery
Batteries are notorious for dying over the winter. If you simply leave the battery in the cold, it will self-discharge, and if it freezes completely, it can crack the casing or short out internally. A dead battery in spring is frustrating, but a ruined battery is just an unnecessary expense.
- Remove the battery: Take the battery out of the jet ski to prevent any parasitic drain from the electronics.
- Clean the terminals: Scrub off any white corrosion using a wire brush and a mixture of baking soda and water.
- Store in a warm, dry place: Keep the battery in a garage or basement where it won’t freeze.
- Use a trickle charger: Connect it to a “maintainer” or smart charger. These devices provide a slow, steady charge without overcharging, keeping the battery healthy for the entire off-season.
Inspect and Lubricate Moving Parts
Just because the jet ski isn’t moving for a few months doesn’t mean the moving parts should be neglected. Rust is the enemy of bearings, cables, and jets. Taking a few minutes to lubricate now will ensure your throttle doesn’t stick and your steering doesn’t feel gritty come summer.
- Grease the fittings: Use a grease gun to pump marine grease into the jet pump’s grease fittings (if equipped) to push out any water that may have seeped in.
- Lube the cables: Spray a silicone-based lubricant down the throttle and reverse cables. Water can get inside the cable housings and cause them to seize up over winter.
- Anti-seize on bolts: Apply a dab of anti-seize compound to bolts you frequently remove (like the seat latch or pump bolts) to prevent them from welding themselves in place due to corrosion.
Don’t Forget the Ride
It’s easy to focus all your energy on the jet ski and forget that your trailer is just as important. A rusted bearing or a flat tire on the trailer can ruin your first trip to the ramp in the spring.
- Inspect the tires: Check for dry rot or cracks. If the trailer is sitting for months, move it slightly every few weeks to prevent flat spots from forming on the tires.
- Grease the bearings: If your trailer has bearing buddies, pump fresh grease into them to force out any moisture that could freeze and crack the hubs.
- Check the lights: Spray electrical connections with dielectric grease to prevent corrosion. There’s nothing worse than finding out your lights are out when you’re trying to hit the road in April.
A Spring Checklist
When spring arrives, it’s tempting to just fire it up and go. Hold on. A few quick checks save all that hard work you did last fall.
- Reinstall the battery and make sure it’s charged.
- Give the hull a once-over for any cracks or damage.
- Hook up the garden hose and start the engine to confirm water is flowing through the cooling system.
Winterizing takes a few hours, but it’s worth it. You’re not just storing a machine; you’re making sure next summer starts exactly the way it should: wide open and worry-free.
