How To Winterize Your Jet Ski For Winter Storage

As the cold weather rolls in, now is the time we start thinking about your jet ski and getting it winterized. It might not be the most exciting task, but it’s something that must be done for most jet ski models.

Winterizing is especially important if you live in a place where temperatures drop below 40°F (5°C). You’d be surprised by the number of people who forget this step, so please don’t forget!

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

Checklist of What you need:

You’ll need some items for your jet ski that will be used for multiple years.

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

How To Winterize Your Jet Ski

The winterizing process involves adding fuel stabilizer, flushing with antifreeze, fogging the cylinders. Also, it’s good to disconnect the battery connections, and grease some components.

Here is a great video showing the process.

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

1: Add Fuel Stabilizer

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

If you’re wondering if the fuel tank should be full or nearly empty, it’s your pick.

You’ll add the fuel stabilizer to your jet ski 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 step; it involves removing the water from the engine and exhaust system of your jet ski!

The way you remove water from your jet ski engine is by using marine-grade antifreeze. Below is the list of engine winterizing steps for flushing with marine antifreeze.

1. Level the jet ski to the ground.
2. Connect the drill pump to the jet ski’s 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 jet ski engine.

You want antifreeze coming out the exhaust, nozzle, jet pump area, or the jet ski’s 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 jet ski engine off, as something is not working right!!! Video below:

The jet ski owner’s manual suggests using an air compressor for removing any water, but I prefer to use marine antifreeze. I find drill pumps easier for people than an air compressor.

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

3: Coat & Fog Internal Engine Parts

The third step involves the jet ski engine and fogging it.

The reason to fog engines is to coat the few internal metal components to prevent rusting during periods of inactivity.

Fogging the engine of an jet ski requires removing all spark plugs and spray fogging oil into each cylinder for about 3 seconds. The video below shows you how to fog the engine:

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

4: Remove Jet Ski Battery And Charge It

The reality is that jet ski batteries will go flat during the winter of inactivity, so it’s in our best judgment to remove them and keep them dry and above freezing, or we run the risk of dead jet ski batteries next riding season.

Ideally, use smart battery chargers that manage charging automatically. Alternatively, charge the jet ski batteries every other month.

Will you have dead jet ski batteries if they don’t get charged over winter? Maybe. The biggest complaint at the start of the jet ski season I get from people is that their jet ski 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 prove effective in maintaining battery life throughout the cold season. What I do is get one solar charger, as I keep my jet ski outside, and get 5 years out of my batteries, plus it’s so easy after doing the winterization.

The solar charger doesn’t need direct sunlight and will keep your battery 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 WD40 silicone spray lubricant on all metal and electrical parts of the jet ski, including the engine and jet pump area.

Make sure you let the jet ski sit for 15 minutes and air out because that WD40 stuff is flammable!!!

Also, lubricate the jet ski’s throttle and steering cables with marine grease.

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

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

6: Put The Jet Ski Cover On

Do not leave the cover off after you winterize; this is very important! The cover keeps the snow and more importantly, rodents, spiders and other critters from getting in and eating or trying to destroy your jet ski.

Rodents like the taste of rubber and plastic, so put your cover on the cover, if you ask me.

Please consider shrink-wrapping so you can better protect your jet ski. Shrink-wrapping keeps your machine in near-perfect condition; snow and rain won’t affect it. Even a little can help. Rodents often chew on plastic and rubber found on jet skis; take some action, since even small effort beats doing nothing.

How To de-winterize

At the end of winter, you’ll need the watercraft prepared for the summer.

The process is super simple, I bet many of you have done it without realizing it.

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

1. Charge the jet ski battery.
2. Replace spark plugs.
3. Top up the gas tank with fresh gas.
4. Ride the jet ski.

Note: If you go for one ride after winterization, you will need winterization again. Once the engine runs in water, it’s no longer winterized.

Learn more about this process; see my post here.