Summerize / De-Winterize Your Jet Ski In 11 Easy Steps

Are you eager to embrace the sun-drenched days of summer?

As the temperature rises and the days grow longer, it’s time to dust off your jet ski and get it ready for some thrilling adventures on the water.

Whether you’re a seasoned rider or a newcomer to the exhilarating world of jet skis, this guide will walk you through the essential steps to ensure your watercraft is primed and prepared for a season filled with fun, excitement, and unforgettable moments on the waves!

Summerizing

To get ready for the summer, you need to do a de-winterize or summerize for your jet skis.

The reason you do winterization to begin with is that it will be sitting for a long time, 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, the process for the summer is super simple, far simpler than anything you had to do in the winter. But it’s still something I suggest you do so the jet ski is ready for the new riding season.

Many Jet Skiers Forget About Doing It

If you forget about the de-winterize it’s not as bad as forgetting the winterize.

The process is so simple that you may do it without realizing it. But let’s make sure you do it right.

How To Do A Jet Ski De-Winterize

The proper steps for a jet ski are, remove the cover, then the seats. Then you must charge and reinstall the battery. Replacing the spark plugs is a good idea as they tend to foul when fogging the engine. Put in some fresh gas as it goes bad when it sits. If you haven’t done so already, now would be a good time to do an oil change for your jet skis.

There is more in the de-winterize process, so here are full the steps below.

1. Charge The Battery

Before you do anything, how about you charge your battery, if you have not done so already.

I have a love-hate relationship with jet ski batteries. If anything gives you trouble at the start of the riding season, it’s more than likely the battery.

Do It The Night Before

I find it best to always charge the battery overnight using a smart charger. Overnight charging is best as the craft is supposed to stay in during that time as covered here.

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

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

2. Replace The Spark Plugs

I change the spark plugs in my jet skis annually, using the recommended ones from the owner’s manual. They will be pre-gapped, so don’t adjust them.

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

Unfortunately for many, winterizing can foul the old spark plugs, and this simple and affordable step prevents future running issues.

3. Add Fresh Gas

The amount of gas you keep in a boat or PWC over winter sparks debate.

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

Starting the season, I fill up the tank using premium gas as a way of diluting 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 using premium fuel.

4. Change The Engine Oil And Oil Filter

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

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

Changing the oil before the riding season or when not riding is a matter of personal preference. I usually opt for doing it during the winter because parts and labor are often less expensive.

New Oil While It Sits

While the craft sits, I like it having 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

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

Before the riding season, and even before you put it in the water, you need a look at the drain plugs.

If the drain plugs are damaged, or the o-ring is damaged or missing, you need new ones (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

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 what 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 local dealership. Mixing can clog the cooling system and create a messy problem that requires fixing.

8. 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 must grease your trailer bearings every year or however many miles your trailer’s manufacturer recommends.

Here is a great video showing you the process to greasing the bearings of a trailer.

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

Straps

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. Washing

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.

What I like to do, 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 ski into the water while attached to the trailer, ensuring the drain plugs are secure and avoiding sandy or rocky areas.

Taking 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.

11. Water Test It

When you pass the leak test, the next thing on the list is getting it out on the water and ride.

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

It’s important to note that as soon as the jet ski is started in water, it’s officially ready for the summer.

Let The Dealership Do It?

The de winterize process is not hard, but if you don’t have the time to do it, you might as well let the dealership do it. Many will even come to your house and do it at your drive up port or trailer.

The service is not free, but it’s a nice piece of mind.