How To Winterize Your Jet Ski For Winter Storage

As the cold weather rolls in, it’s time you think about your jet skis and how you’ll prepare them for winter. It might not be the most exciting task, but it’s necessary once you understand how it protects your engine.

Winterizing is especially important if you live somewhere that drops below 40°F (5°C). You’d be surprised how many people skip this step, so don’t forget about it!

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 shows how adding a fuel stabilizer, flushing with antifreeze, and fogging the cylinders all help protect your engine. It’s also a good idea to disconnect the battery connections and to grease some components.

Here is a great video showing the process.

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

1: Add Fuel Stabilizer

The first step for the winterize process is adding fuel stabilizer to 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 to 20 gallons. PWCs will have a 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 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 one; it involves removing the water from the engine and exhaust system of your jet ski!

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

1. Level the craft 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 jet ski engine.

You want antifreeze coming out the exhaust, nozzle, jet pump area, or the jet skis 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 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 a 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 how fogging protects those metal parts will make you appreciate this step even more.

Fogging the engine of a engine requires removing all spark plugs and spraying fogging oil into each cylinder for about 3 seconds. The video below shows you how you should 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 a battery will go flat during the winter of inactivity, 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 jet ski 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 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 winterize.

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 WD-40 silicone spray lubricant on all metal and electrical parts of the jet ski, including the engine and jet pump area.

Make sure to let the jet ski 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 jet ski will maintain its appearance for years!

6: Put The Cover On

Do not leave the cover off after you winterize; this is a very important step. The cover keeps out snow and, more importantly, rodents, spiders, and other critters that could chew or damage your PWC.

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 watercraft 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 PWCs, so taking precautions now is much better than dealing with the damage later.

How To de-winterize

At the end of winter, you’ll need to get your jet ski ready for the summer.

The process is very simple; many of you have probably done it without even realizing it.

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

1. Charge the 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 winterize again. Once the engine runs in water, it’s no longer winterized.

Learn more about this process; see my post here.