If you live anywhere that sees 4 different seasons of weather, knowing how to winterize your personal watercraft (PWC) for storage is not only vital to protect your investments, but to save hundreds, if not thousands, of dollars in repairs and replacement parts.

If you’re wondering how to winterize your PWC for storage, here are the standard steps:

  • Drain & Flush Fluids
  • Oiling & Lubricating
  • Add fuel stabilizers
  • Washing, drying, and waxing the entire craft
  • Disconnecting and removing the battery
  • Proper storage of the entire craft

While, on the surface, these may not all seem crucial, each contributes to the ultimate goals of protecting your PWC.

Winterizing Your PWC for Storage

Winterizing your PWC for the colder off-season helps increase the unit’s longevity and performance. Avoid serious structural and mechanical issues like rust, corrosion, and damage from freezing water.

Here’s what you’ll need to winterize your PWC:

  • Soap
  • Water
  • Fuel stabilizing fluid
  • Fogging oil spray
  • Silicone lubricant spray
  • Antifreeze
  • Clean towels
  • PWC Cover

Here’s how (and why) each of these steps is important when winterizing your PWC for storage.

Draining & Flushing

Water in the engine compartment can freeze and cause a great deal of damage to the engine, leading to an engine replacement that may cost more than the unit itself. There will also be water inside your jet ski’s cooling system, which is how it keeps the engine and other moving parts from overheating. 

To Flush:

  1. Connect a garden hose to the flush fitting. DON’T TURN ON THE WATER.
  2. Start the engine.
  3. Turn on the water to begin flushing, flush for 1-2 minutes.
  4. Turn off the water to end flushing.
  5. Give the engine a few revs to 3-4,000 rpm for about 15 seconds. This will flush any remaining water in the system.
  6. Stop the engine.

Again, be sure to follow the specific instructions in your owner’s manual to ensure you perform a proper and thorough flush of your PWC’s system. You may also want to read Can You Run a Waverunner Out of Water.

Do a full jet ski service:

I almost always do an oil and filter change at the end of each season. I replace the spark plugs, as well. You can winterize your ski using this article as a guide without doing a service. If you prefer to do a service, check out my posts on changing oil and changing spark plugs.

You should do the service after flushing and before final preparation that follows.

Oiling and Lubricating

To keep engine parts from corroding, spray fogging oil into the spark plug cylinders. Crank the motor a few times to spread it through the cylinder. Once all of these parts are reassembled, lubricate the seals and cables using the protectant recommended by the manufacturer.

Fogging oil is a petroleum-based aerosol treatment for long-term lubrication and corrosion protection. Used correctly, fogging oil creates a thin protective coating on internal metal components. Unlike standard motor oils, it remains intact over time. Without it, engine oils  will drain from cylinder walls, leaving them exposed to rust and corrosion.

To apply fogging oil:

This is best done when changing spark plugs. After the old plugs are removed, spray a little fogging oil into each cylinder. Crank the motor for a few seconds to distribute the oil throughout the cylinders.

Then install new spark plugs, making sure to check for proper gap before inserting them. Also look at the old plugs to determine whether you need to leave the cap on or remove it.

Tighten your plugs by hand until snug, then use a spark plug socket to tighten with a few pounds of torque. Don’t over tighten spark plug.

The Author’s Video on Changing Sea Doo Spark Plugs

Adding Fuel & Stabilizers

I also fill the gas tank up to the top with fresh fuel and a use a stabilizer to avoid damage from the alcohol or moisture in the gas. By maintaining a full tank, you help prevent corrosion that can accumulate in the upper portions of an empty tank when sitting idle for a long period of time.

Run the engine in 30-second bursts to get the stabilizer well mixed in the fuel. After stabilizing your fuel, you should lubricate all seals and cabling using a lubricant and protectant recommended by the PWC manufacturer.

Washing, Drying, and Waxing 

To properly winterize your personal watercraft, you need wash the inside of the hull with a degreaser and the outside with auto wash soap (not dish soap or laundry detergent!)

After scrubbing the hull, wash and wax the shell to protect it from UV damage.

Finally, clean the bilge and wash away any excess grime.

Disconnecting the Battery

Leaving your PWC battery connected over the winter can reduce both its charge and overall battery life.

Here how to disconnect the battery:

  1. First, remove the negative connection, then the positive.
  2. Lift the battery out of the chassis. 
  3. Scrub the terminals and battery case with a thin paste of baking soda and water
  4. Top off each cell with distilled water, for non-sealed batteries. Use only distilled water.
  5. Store your battery in a cool, dry, well-ventilated area, where the temperature is unlikely to drop below 40 degrees.
  6. Apply a light coat of battery terminal grease
  7. Place it on a trickle charger, I use the inexpensive Battery Tender 800 from Amazon for 2 PWC’s, 2 cars and 2 other boat batteries.

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Please Note: While these are good general guidelines for all personal watercraft, again, always be sure to consult the manufacturer owner’s manual for your make and model for specific instructions for winterization.

Can I Leave My PWC in Water?

The answer is yes…and no.

If you’ve been using you PWC in freshwater, like a lake, it’s probably safe to keep it in the water for a week or two. Freshwater takes much longer than salt water to corrode metal components (and destroy your ride).

Still, even is the risk of corrosion is much lower, you should still keep an eye on things like the pond scum and other pollutants that build on the bottom of the boats. If you have a lift or floating dock, that helps somewhat. But winter on-water storage is different from summer-time storage. It will be sitting unattended in extreme weather for months at a time.

You should never store your PWC in the water if possible. Even outside driveway trailer or PWC stand storage is much better than leaving it on the water in winter.

Where Should I Store My PWC?

Although a wide variety of storage options are available, most manufacturers tend to agree on where not to store them, and that’s outside…exposed to the elements. 

Marinas and rented storage units are both viable options, but most PWC owners chose to make room in their own garage. Besides being free, home storage has the added benefit of security (ie: you can keep a close eye on your baby), it’s a convenient location for repairs and upgrades, as well as being sheltered from winter weather.

Keep in mind, even when storing your personal watercraft indoors, it’s important to have a properly fitting cover for each. This helps protect from the gunk and grime that collects when the engine and other mechanical parts are exposed to dirt and dust. For more on storage, read our full guide.

Ten Things to Check or Replace While Your PWC is Out of the Water

When your PWC is out of the water and getting ready to go into storage, you will find that it is a good time to do an inspection and make sure everything is in good condition. Here is a list of 10 things you may want to check or replace before your PWC goes into storage.

  1. Spark plugs
  2. Hoses
  3. Power steering/cables
  4. Test the bilge pump
  5. Clean and replace the drain plug
  6. Rudder and shafts
  7. Inspect the prop
  8. Check/repair the trim
  9. Inspect personal flotation devices
  10. Test the fire extinguisher/check expiration date

It’s important to know how big of a dent all of this is going to make in your budget.

Should I Have My PWC Winterized Professionally?

Getting a PWC professionally winterized by a licensed mechanic typically runs $600-$800, your local dealer should be able to give you a narrower estimate. You can save hundreds of dollars doing it yourself. Watch the introduction to winterizing video at the beginning of this article. Very few tools are needed, and it only takes 60-90 minutes if you are a first time mechanic.

If you have experience with jet skis and how to winterize them, you can do it yourself in 30-45 minutes and save 50-75% off the shop fees. It takes us 2-3 hours and $125 per ski in supplies to completely winterize our 2 Sea Doo RX 260’s. Compare that to $400-600 dealer prices. And you don’t have to transport it to the dealer and pick it up afterwards.

If a PWC is not properly maintained during the off season, owners can be in for expensive engine repairs in the spring. Again, repairs that can often exceed the value of the jet ski and, more importantly, keep you from getting back on the water. 

PS – Don’t forget that how we de-winterize our personal watercraft is just as important as how we put it into storage!

Tim Conner, M.D. started boating in 1974. He has been involved in recreational boating continuously since then. Dr. Conner has been active in boating and watersports safety education for decades.

He rode his first jet ski in 1997, and rejoined the personal watercraft arena in 2012 with a Sea-Doo GTX 155, followed by 2 supercharged SeaDoos. Scuba certification came in 1988, and he and the family have traveled the world snorkeling and scuba diving for decades. The family has recently taken up paddle boarding, with wakeboards and kitesurfing the next challenges for my adult kids. See the About page for more.