How to Winterize, Fog, Cover, and Prepare Your Jet Ski for Winter Storage and Peace of Mind

As the cold weather rolls in, it’s time you think about your jet ski or boat and preparing them for the cold weather using proper winterization steps.

Winterizing any watercraft is especially important if you live somewhere that temperatures drop below 40°F (5°C). You’d be surprised by the many personal watercraft owners that tend to skip this step, so don’t forget about it!

Note: These winterizing steps focus on Sea-Doo watercraft models, but the process is nearly the same for Yamaha and Kawasaki Jet Skis, too.

Checklist – What you need

The winterizing process will require you to get a few items as part of your overall PWC maintenance checklist.

1. 1-Gal (per machine) of RV/Marine Antifreeze.
2. Marine fuel stabilizer.
3. Fogging spray storage oil.
4. WD-40 Silicone Spray Lubricant or similar product.

How To Winterize

The basic idea of winterizing is to add fuel stabilizer, flush with antifreeze, and fog the engine cylinders, drain the water, and provide full moisture protection. It’s also a good idea to disconnect the jet ski battery connections and to grease some components like the steering cable.

Here is a great video showing the steps:

If you’re like me, you need written instructions, so I’ve listed them below.

1: Add Fuel Stabilizer

The first step is adding a fuel stabilizer to the PWC gas tank to keep the fuel in great shape as the vessel sits. The fuel stabilizer bottles generally include measurements suitable for a jet ski gas tank ranging from 2.5 to 20 gallons. Jet Skis will have 5 to 20-gallon gas tank; often, 15 to 18 are the most common.

If you’re wondering if the fuel tank should be full or nearly empty, it’s going to be your pick. It’s a different story for some boats, but I tend to keep my Sea-Doo Spark nearly empty.

You’ll add the fuel stabilizer to your gas tank first; it ensures it mixes well and reaches all the fuel lines before starting the next steps.

2: Flush With Antifreeze

The second step is an important one; it involves removing the water from the engine and exhaust system of a jet ski! This is super important for Yamaha waverunners, Kawasaki Jet Skis and most Sea-Doo’s with a supercharger or a 2-stroke. Even the 4-stroke Sea-Doo watercraft benefit, as they still take in water to cool the exhaust system.

The way to remove water from a jet ski engine is by using marine-grade antifreeze. Below is the list of engine winterizing steps to follow when flushing with marine antifreeze.

1. Level the jet ski to the ground.
2. Connect the drill pump to the flush port and get the antifreeze ready.
3. Turn the engine on.
4. Turn on the drill pump and use the entire gallon of antifreeze.
5. When you use up the whole gallon of antifreeze, turn off the drill pump, then switch off the engine.

You want antifreeze coming out the exhaust, nozzle, jet pump area, or the jet ski side discharge port. If you don’t see antifreeze come out of ONE of these ports after 20 seconds, turn the pump off and then the engine off, as something is not working right!!! Video below:

The owner’s manual suggests using a air compressor to remove any water, but I prefer to use a marine antifreeze. I find a drill pump easier for people to use than an air compressor.

Add water? For marine and RV antifreeze, it should come pre-diluted and ready to use. Additionally, water remains in the cooling system; hence why you need to do the whole winterizing process, as it inevitably blends with the water. So, adding more water to your jug is not what we want.

3: Coat & Fog Internal Engine Parts

The third step involves the engine and fogging it.

Understanding that fogging protects those metal parts will make you appreciate this step even more.

Fogging the jet ski engine requires removing all spark plugs and spraying fogging oil into each cylinder for about 3 seconds. The video below shows you the steps for fogging your jet ski engine:

At the start of the riding season, I suggest replacing spark plugs because of the effect of the fogging oil.

4: Remove the Battery And Charge It

The reality is that a jet ski battery will go flat while in long-term PWC storage, so it’s in our best judgment to remove it and keep it dry and above freezing, or we run the risk of a dead battery next riding season.

Ideally, use a smart battery charger that manages charging automatically. Alternatively, remember to charge the battery every other month.

Will you have dead batteries if they don’t get charged over winter? Maybe. The biggest complaint at the start of the season I get from people is that their jet ski’s won’t start, and it’s because of the battery. Their batteries are small and don’t get used enough, which is why they die easily. Battery chargers are effective in maintaining battery life throughout the cold season. What I do is get one solar charger, as I keep my Sea-Doo outside, and get 5 years out of my batteries, plus it’s so easy to do after doing a winterize.

The solar charger doesn’t need direct sunlight and will keep batteries active and happy! It’s so stupidly easy and effective that I don’t know why the manufacturers don’t just have the solar panels already on the covers.

5: Spray WD40 Specialist Silicone Lubricant

One commonly overlooked step is spraying WD-40 silicone spray lubricant on all metal and electrical parts of a jet ski, including the engine and pump area.

Make sure you let the jet skis sit for 15 minutes and air out, because that WD-40 stuff is flammable!

Also, lubricate the throttle and steering cables with a marine grease.

Avoid regular WD-40; use a silicone version instead. The regular stuff doesn’t coat, it merely displaces water.

Here’s a useful tip for those residing near saltwater: regularly apply a silicone spray on the engine and pump areas. Repeat this yearly routine, allowing it to air dry for 15 minutes each time, and your Sea-Doo will maintain its appearance for years!

6: Put The PWC Cover On

Do not leave the cover off after winterizing your craft – the PWC cover is essential for moisture damage prevention; this is a critical step that far too many ignore. The cover keeps out snow and, more importantly, rodents, spiders, and other critters that could chew or damage your jet ski.

Rodents especially like rubber and plastic, so always keep the cover on. In fact, doubling up on protection is a smart move.

Please consider shrink-wrapping for even better protection. Shrink-wrapping keeps your jet ski in near-perfect condition since snow and rain won’t affect it. Even a small effort helps. Rodents often chew on the plastic and rubber parts of a jet ski, so taking precautions now is much better than dealing with the damage later.

What about de-winterizing your jet ski?

At the end of winter, you’ll need to get your Sea-Doo ready for the summer.

The steps are very simple; many of you have probably done it without even realizing it when you hop on and go for a ride in the Spring.

Below are the steps, but I’ll link the full guide, too.

1. Charge the battery.
2. Replace spark plugs.
3. Make sure you top up the gas tank with fresh gas.
4. Ride the craft.

Note: If you go for a ride after you winterized the engine, you must redo the winterization again. Once the PWC engine runs in water, it’s no longer winterized.

Learn more about this process; see my post here.