How To De-Winterize Your Jet Ski In 11 Simple Steps

At the start of a new riding season, I often get a huge list of questions from readers about getting their jet ski ready. Things like, what steps should I do after my jet ski has been sitting? Do I need to de-winterize my watercraft? What if I didn’t do anything over the winter, is my jet ski okay?

In this post, I want to go over the steps to get your jet ski ready for the new riding season. The process is not hard, but there are a few key points that you must understand before you hit the water.

So let’s dig in and go over what you need to do below!

What in The World is “De-Winterizing” A Jet Ski?

De-winterizing or summerizing a jet ski is merely getting it ready for the warmer weather.

You winterize a jet ski because it’s going to be sitting, often in below freezing temps, so it needs to be prepared for that. This process is involved, and some stuff is removed, unplugged or coated so much they must be replaced.

To be honest, de-winterizing is super simple, far simpler than winterizing. But it’s still something I suggest you do so the watercraft is ready for the new riding season.

What If You Don’t De-Winterize Your Jet Ski?

It’s not the end of the world if you don’t de-winterize your jet ski.

The process is so simple that you may do it without realizing it. Follow the steps below to see how much you need to do. Forgetting to de-winterize is not as bad as forgetting to winterize.

How To De-Winterize Your PWC

1. Charge Your Battery

Before you do anything, now is a good time to charge your battery, if you have not done so already.

I have a love-hate relationship with PWC batteries. If anything is going to give you trouble at the start of the riding season, it’s more than likely going to be the battery.

1 amp battery charger on table.

Charge The Night Before

I always charge the PWC battery overnight with a smart charger.

The next day, I disconnect the charger and test the battery with a load tester before installing it.

This helps prevent any surprises or extra work in case the battery isn’t really charged.

2. Change Spark Plugs

I change the spark plugs in my jet skis annually, using the recommended ones from the owner’s manual. They should be pre-gapped, no need to adjust them.

Stick to the manufacturer’s recommended plugs; fancy ones aren’t better!

Winterizing can foul the old plugs, and this simple and affordable step prevents future running issues.

3. Add Fresh Gas

Justrite safety gas can.

The amount of gas to keep in a boat or jet ski over winter sparks debate.

I store mine near empty (one or two bars on gauge) with fuel stabilizer because it can go bad, no matter what you do. Less fuel, fewer problems if you ask me.

Starting the season, I fill up with premium gas to dilute the bad gas. This avoids the hassle of removing bad gas from a full tank and reduces the risk of having a full gas tank near my home (dangerous and theft issues).

It works well for me, but opinions vary.

Note: I use regular gas for my non-supercharged jet skis. But for supercharged jet skis, I always use premium, even if the manufacturer suggests regular. Supercharged engines perform better with premium fuel.

4. Change The Engine Oil And Oil Filter

Pointing out the RXP-X engine compartment parts.

If you didn’t change the oil during winterization, now would be a good time.

Don’t wait until the middle of the riding season, as dealerships get weeks behind, and parts also start to get limited when they get busy.

Changing the oil before the riding season or during winterization is a matter of personal preference. I usually opt to do it during winterization because parts and labor are often less expensive in the winter.

Fresh Oil While It Sits

While the craft sits, I like it with fresh new oil, as old oil becomes contaminated and acidic. But doing your oil change now is not bad; many like doing it now as you start the season with fresh oil.

Either way, it honestly doesn’t matter; just make sure you at least change the oil and oil filter once a year, along with the spark plugs.

5. Drain Plugs

Drain plug being pointed out on Yamaha EX.

The drain plugs are often overlooked by many owners, and it’s one of the more essential components of your waverunner.

Before the riding season, and even before you put it in the water, you should check your drain plugs.

If the drain plugs are damaged, or the o-ring is damaged or missing, you need to get a new drain plug (or o-ring).

A damaged drain plug or its o-ring can cause your machine to sink, so you must check them often.

6. Sacrificial Anode

Pointing to the sacrificial anode on Sea-Doo near pump.

Also, check the sacrificial anode near the rear, close to the pump and nozzle when inspecting drain plugs.

This small metal piece with a bolt through it erodes faster than other metal parts to protect your watercraft.

If it’s damaged or missing, replace it!

7. Coolant

This is only for Sea-Doo’s as they use a closed-loop cooling system, but make sure to check your coolant levels.

Check the overflow tank to see how much coolant you have. You will have a high and low bar on the tank; you want to be between the two.

Important: Use the coolant that matches your Sea-Doo’s year – green or orange/pink. Never mix them. If unsure, consult your dealer. Mixing can clog the cooling system and create a messy problem that requires fixing.

8. Your Trailer

Let’s not forget to check your trailer too.

Ensure you have the correct air pressure in your tires and grease the bearings. Ideally, you should grease your trailer bearings every year or however many miles your trailer’s manufacturer recommends.

Here is a great video showing you how to grease the bearings of a trailer.

Don’t forget to check the trailer lights and any damage to the trailer.


Replace torn or sun-faded straps.

Pay attention to the front bow strap; it can snap while driving. Without rear straps, the ski might end up on the road.

New straps are cheaper than fiberglass repairs. If your straps are over 3 years old, damaged, or sun-faded, replace them!

You can get front winch straps here (Amazon Link Ad).

You can get rear straps here (Amazon Link Ad).

9. Wash Your Jet Ski

Before heading to the water, I like to give the jet ski a good wash. Marine soap works best, but car soap will work too.

Since the jet ski will be sitting more in the sun now that it’s getting ready for the season, I like spraying the seat with a vinyl protectant (Amazon Link Ad).

The seats are made of vinyl, and if it gets dry or sun-damaged, it tends to tear or leave annoying black spots that look like mold. Spraying vinyl protectant every time I can remember does help protect the seats.

10. Leaks

To test for leaks, back the PWC into the water while attached to the trailer, ensuring the drain plugs are secure and avoiding sandy or rocky areas.

With the seat off, let the engine idle without revving, and observe if water is taken on.

This method also helps identify other potential issues before a full launch.

If preferred, you can conduct a similar test at home using a garden hose, remembering to start the engine before the water and to turn the water off before the engine.

Flushing Sea-Doo GTI on garden hose water coming out.

11. Water Test It

When the jet ski passes the leak test, the next thing to do is take it out on the water and ride.

Spend the first 5 minutes of your ride going easy and if everything seems fine, ride it like normal.

As soon as the jet ski is started in water, it’s been officially de-winterized. So if you want to winterize it again for some reason, it will need to do so after it’s been run in the water.

Let The Dealership Do It?

You don’t need the dealership to de-winterize your jet ski.

The most complex tasks are the spark plugs and oil change.

If they handle these, you can let them do a full de-winterize. Typically, dealerships connect the battery, change spark plugs, and run it on the hose – tasks most can handle themselves. No need for the dealership unless you prefer it.



I started working at a power sports dealership in 2007, I worked in parts, service counter, and as a technician before moving to sales in 2013. I created in 2014 to answer common watercraft questions I would get from people. Now managing the site full-time, I continue to provide advice and web tools for my readers about watercraft. I've owned several watercraft, with a Sea-Doo Spark as my current main PWC.


  1. Great articles, Steven, both he summerizing and the winterizing (and the new maintenance one). One question: Could you provide a bit more detail re: oil filters? Easy to buy, and simply located in the engine bay, or hidden deep underneath the engine?


    • Thank you for the kind words. For the oil filters, you want to use the one the manufacturer recommends. You should also use the manufacturer’s recommended oil. You can get the oil and filter at the dealership but most of the time you can find them online from eBay and Amazon, just make sure you get the right kit – your owner’s manual will tell you the part numbers you need. The oil filter is super easy to get to on a Sea-Doo, this video does a great job of showing it… Getting the cap off the Sea-Doo oil filter can be tricky as you need to wiggle it out.


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