Do Jet Boats Need To Be Winterized? – How To Winterize?

For some reason, people think jet boats don’t need to be winterized.

Jet boats do need to be winterized, but it’s not as involved as other boats. This could be where the confusion comes from.

Why You Need To Winterize Your Jet Boat

The biggest reason you winterize any boat is to get the water out of the engine.

All boats use lake or ocean water to cool the engine.

The problem with water is that it expands when it gets cold. This water is located in tight spots, and if the water doesn’t have enough room to expand, it will grow and break your engine apart.

Breaking the metal of the engine block or exhaust is not good as it can destroy them.

So you must get the water out before it gets cold.

What About Closed-Loop Cooling?

Some jet boats like Sea-Doo, Scarab, and Chaparral use a closed-loop cooling system. So they don’t take in any water, unlike the Yamaha Jet Boats.

While the engine doesn’t take in the water, they still take in water to cool and muffle the exhaust. Not only that, but if your jet boat has a supercharger, it also has an intercooler that is cooled by outside water. The intercooler for sure needs to be flushed out, and many jet boats have a dedicated port for that.

How Do You Winterize A Jet Boat?

Here is a great video that shows you how to winterize a jet boat.

Make sure to add some STA-BIL to the gas to keep it fresh while it sits for a few months. Stick to Marine STA-BIL like this stuff on Amazon (Amazon Link Ad).

You’ll need at least 1 gallon of the Pink RV Anti-Freeze per engine. You can get this at any boat or camping store.

I also like to spray down the whole engine compartment with WD-40. This is to stop corrosion but also to keep mice away. They like the taste of rubber but not the taste of the WD-40. Plus, it makes it too slippery for them.

With the boat on land, make sure to take the drain plugs out. I’ve seen people not do this and have the boat sink on land. Keep in mind boats are like a giant bucket, so rainwater can fill up the hull if you don’t take the drain plugs out. Just make sure to put them back in before going into the water.

Super Important – You need to put your battery on a charger or use a solar charger when you’re not using your boat. Flipping the battery switch to off is not good enough. You need to keep the battery active and using a smart battery charger (Amazon Link Ad), or a solar charger is the best way to do this. For solar chargers, you want to buy 10-watt ones with a built-in tender like this one on Amazon (Amazon Link Ad).

If you can store the battery somewhere warm like your garage, then do that. Just make sure to keep it somewhere ventilated and somewhere a smart charger can charge it.

Should I Change My Oil In My Jet Boat When I Winterize It?

I usually do my oil changes during the winter. Not because it’s better but because supplies or labor to get it done is cheaper in the winter.

You’ll often find many dealerships willing to do an oil change with winterization combined for cheaper than it usually costs to get just the oil change in the summer.

If you do it yourself, you’ll find many of the parts going on sale around the winter too.

Plus, when the season starts, I’m ready to get on the water and have some fun. Dealing with oil changes then is not worth it.

Another reason to change your oil in the winter is that old oil has corrosive properties in it. It’s better to store your boat with new oil than old oil.

Store With A Full Tank Of Gas?

I don’t store any jet boat with a full tank of gas.

The gas will expand and dump out, which is wasteful. Not only that, but you’ll need to use more STA-BIL.

I like having less than a quarter tank of gas. Then when the season starts, fill it up with fresh gas.

The reason people put a full tank of gas in their boat when they store it is to stop condensation. I find it’s better to have little gas with little condensation then to have a lot of gas that could have gone bad with little condensation. At the start of the season just fill the tank up with some fresh gas and you’ll be fine.

What If It Doesn’t Get Cold Where I live?

If it doesn’t get below 40F (4C) where you live, then winterizing your boat is different.

I would still consider running the RV Anti-Freeze through it, but that is up to you.

Most of what you need to do is fog the motor, put STA-BIL in the gas, and keep the battery on charge.

What About The Trailer?

Something everyone forgets is their boat trailer.

You’ll want to make sure you have proper air pressure in the tires before you put it up. If you can, prop the trailer on big blocks so the tires don’t develop a flat spot.

It’s also a good time to grease the bearings on your trailer as this video shows.

How To De-Winterize Your Jet Boat

To de-winterize your jet boat is simple.

  1. Charge the battery overnight. If the battery is bad, replace it.
  2. Replace the spark plugs.
  3. Put drain plugs in.
  4. Take the boat out for a run. You could run it on the water hose if you want, but taking it out to the water is a better test.

And that’s about it.

The biggest thing you’ll need to do is change the spark plugs as they are more than likely bad from fogging the engine.

What Else?

If you’re going to keep your boat outside the best bonus tip I can give you is to get a cover for your cover.

Yes, if you already have a cover on your boat, it’s smart to throw something like a tarp or a second cover over it for long term storage. Tarps don’t always offer the best fit. So what I do is buy a cover like this here on Amazon (Amazon Link Ad) that anchors to the trailer to cover my cover. This fits better than any tarp would.

If there are any trees or dust near your boat, they will find a way in with all the rain that is coming. This means gunk will build up even if you have a cover on your jet boat.

Not only that, but boat covers are bad about stretching and holding water. This is the worst as it destroys your cover over time, and the dirty water attracts bugs and animals.

Getting a cover to put over your boat and its cover is a smart idea! You’ll thank me next season when clean up is easy.

What If I Want To Take My Jet Boat Out During The Winter?

If you take your jet boat out during the winter after it’s been winterized, you’ll need to winterize it after you’re done.

As soon as the boat is put back in the water, it’s not winterized anymore.

This also means you can’t winterize a jet boat while it’s in the water. The jet boat needs to be out of the water so you can run the RV Anti-Freeze through it. If it’s in the water, it will suck up the lake or ocean water instead, which de-winterizes it.

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