Do Jet Boats Need to be Winterized?

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Jet boats are super fun, speedy, stylish watercraft. Jet boats are basically grown-up jetskis. They are great for waterskiing, tubing, and watersport in general. They get up to speed quickly and can make some serious wake. 

When it comes to care and maintenance, are jetboats a lot of work? Do Jet boats need to be winterized?

Yes, you need to winterize your jetboat and keep it out of the water once the weather gets cold. 

In this article, we’ll cover the details on jet boat winterization!


Do jet boats need to be winterized?

Unless you live in warmer climates that stay above 40F (4C), then you DO need to winterize your jet boat. The rule of thumb is that the engine should be taken out of the water during cold periods. If you don’t do this, the expanded water is so powerful that it can crack the engine or the exhaust.

One of the main problems is that water expands as it gets cold.

Even if you have a closed-looping system, you will at the very least need to flush out the intercooler.

Jet boat winterization checklist

The best course of action is to lift the jet boat out of the water. This will allow you to give your precious craft a thorough maintenance check.

You should always follow the instructions of your boat manufacturer and your engine manufacturer. But for a basic overview, here’s what is generally involved in Jet Boat winterization.

1. Fuel fank and filters

By filling the fuel tank, you can avoid any air getting in there. Air can potentially create condensation and moisture. Not everyone likes to keep a full tank of gas in their prized possession over winter. Instead, only keep a small amount of fuel in there that can’t build up too much condensation. It’s essential in your winterization schedule, to add a fuel stabilizer .

This will prevent any unwanted build-up of gunge in the fuel lines. At this point, it would be a good opportunity to replace your fuel filter/water separator.

2. Anti-freeze for inboard engines

If you’re doing this while the craft is in the water, then close off the intake seacock. This is a valve situated in your hull that allows water to flow inwards. 

Draining all water out of the engine is essential.

If you don’t then freeze damage could ruin your engine, causing multiple system failures. Remove the intake hose, which can be tricky due to the clamps. You’ll need around five gallons of a nontoxic undiluted antifreeze, such as No products found..

If you put this in a bucket, or a marine flushing system , you can run it through the hose that’s going to replace the intake hose you took out. As you drain this through, run the engine on idle until you see the antifreeze coming out of the exhaust. 

When you’re done with the winterization process, seal the engine off the best you can so that no cold air can get inside it.

Remember that air turns into moisture as it cools, and that’s exactly what you DON’T want.

Also, apply a lubricating spray oil such as WD40.

3. Change oil and filter

Again, you want a warm engine but switched off. All that gunge in the bottom will do more harm than good if you leave it in there. If you don’t know how to drain the old oil out, then add an oil stabilizer  to your oil. Change your transmission oil  too.

If you’re not confident in changing fluids, consider having the work done professionally. Good maintenance care will extend the life of your engine.

4. Caring for your batteries over winter

Again, super important to remember to winterize your battery by putting it on a battery charger . Or you could trickle-charge with a solar charger , which is super helpful to have around regardless.  

Important miscellaneous winterization tasks

  • Clean out debris build-up for the exhaust. Replace if necessary.
  • Clean out the water injection hose. Replace if necessary.
  • Go around and check ALL hoses for any cracks. Look for bulging as this could indicate collected debris. 
  • Check the clamps holding the hoses in place, looking for any corrosion. Replace if necessary.
  • Open up all the drain plugs in your jet boat, especially if it’s being kept outside where it can collect rainwater.  

Where can I winterize my jet boat?

Hopefully, you’ve decided not to keep it in the water because ice can do so much damage to the body of your craft. Here’s a few ideas for storage over winter:

  • Inside an aerated garage
  • Rented self-storage facility
  • Under a carport
  • Inside an extra-large storage tent
  • Outside, under a good fitting boat cover.

What will happen if I don’t winterize my jet boat?

If you don’t winterize your jet boat, come spring you could find the body and machinery rotted and rusted so badly that you can’t use it. That’s because the craft will suffer from damp and mold.

Oh, and don’t forget about the extensive damage that expanding water damage can do. Burst hoses, pumps, and equipment. The expense of repairs could be so costly that it may total more than the boat is worth.

What happens if I want to go out in my winterized jet boat?

Even if you only want to do a single trip during the winter, you MUST de-winterize the boat, making it usable. Here’s a de-winterization list of jobs to be done:

  • Check the batteries are fully charged or get new ones.
  • Don’t forget to put any drain plugs back into the bottom of the jet boat.
  • Refill the gas tank if you emptied it for winter.
  • Degrease the engine with a quality fogging oil .
  • Inspect all wires, pipes, and belts. 
  • Change the spark plugs to keep that engine running healthily.
  • Turn over the engine to make sure it sounds good. 


If you want to ensure your jet boat lasts you for many years to come, then the winterization tasks are necessary. If you’re not confident enough to do the jobs yourself, for around $300-400, you can get a professional to do the work for you.

It will be money well spent for protecting your craft for the cold months ahead.