Store Jet Ski Gas Tank Full Or Empty? – Long Term?

I don’t know how the topic of how much gas you should store in your boat or jet ski has become such a hotly debated topic, but it has.

Typically, this question comes up around winter, when people store their machines for months. Though, it’s still a problem for anyone who stores their machines for long periods of time, no matter the season.

My opinion and thought process tends to be against the status-quo, but let me explain how much gas you should store in your PWC for long-term storage.

Store It Near Empty

The common answer for storing gas in any boat is to have it full and add fuel stabilizer.

On the other hand, I do the opposite, but I still add stabilizer.

When I store my jet ski, I like having the gas tank near empty (1 or 2 bars on the gas gauge) for storage.

The honest truth is that both ways are fine, but I consider near empty to be slightly better.

Let’s go over the reason for both and why, overall, nearly empty is better.

Storing A Jet Ski With A Full Gas Tank

The reason many in the boating world like to store their fuel tanks full of gasoline is that there are fewer chances for water to get in.

Boats operate in a wet environment, and water just finds a way. This water problem has even gotten worse due to ethanol in gas, which loves water.

The more gas you have in the fuel tank, the less room for air and, more importantly, the water in that air to end up mixing in. Water getting in causes it to go bad and the jet ski to run rough.

With boats having large gas tanks, 30 or 50 gallons or even larger gas tanks, you can see how the chances of water is so much greater.

Jet skis are a bit different, they have at most 20 gallon gas tanks, with some as little as 5 gallons. Even with smaller tanks, I don’t see having a full tank of gas as the better option when storing any boat.

Why Near Empty Is Better:

When I say near empty, I mean one or two bars of gas on the display, or about one or two gallons. Most of the time, it's whatever was left after the last ride of the season, which is often one or two bars. I don't remove any fuel, but instead try to ride my jet ski until I get the fuel tank low enough. 

These are the reasons why I store a jet ski near empty:

  1. Cheaper.
  2. If the gas goes bad, just add more fresh gas.
  3. Safer.
  4. Cuts down on theft.
  5. Cuts down on waste.

Allow me to explore each point in more detail on why a nearly empty gas tank on a jet ski is the better option for winter storage.

1. Cheaper

If you’re storing your jet ski near empty for winter, then you don’t need to buy more gas, unless it’s completely out.

I like to be around one or two bars, at least 1 gallon of gas in the tank, when I store a machine for long-term storage.

When the season is ending, I don’t refill my jet ski, I run it until there is one or two bars on the display, add fuel stabilizer, and I’m done with the fuel. I do other winterization steps too, as talked about here.

You want some gas for the fuel pump and other components that need some to operate correctly. You will burn out your fuel pump if there is none in your tank, so at least leave a gallon of fuel in the tank.

Gas is not cheap and jet skis can hold quite a bit of it, and keeping yours stored near empty will always be cheaper than filling it up for the winter. It’s even cheaper when it comes to adding fuel stabilizer, you don’t need as much as you’re not storing as much gas!

2. If The Gas Goes Bad, Just Add More Fresh Gas

The whole reason someone would store a jet ski full of gas is to keep water out, so it doesn’t go bad.

If there is not a lot of gas in the fuel tank, there isn’t a lot of gas to go bad.

It’s all about dilution.

When the season starts back up, just fill up with some premium. If you kept it near empty, then the 1 gallon of gas that MAY have gone bad is diluted with the 4 to 19 gallons of fresh fuel.

On the other hand, if you kept your jet ski near full and that goes bad, you can’t dilute it. You must suck out the old stuff and then add new fuel.

3. Safer

People store jet skis either in their garage or near their home, and something about a 5 to 20 gallons of gas sitting that close to my home worries me.

Sure, people keep their gas cans, cars and trucks in garages and have no problem, but why have something else to worry about?

If one option is cheaper, safer, and overall easier, I’m going to go with that one and store my jet ski near empty.

4. Cuts Down On Theft

This may not affect everyone, but when gas prices get high, people get bold.

Stealing gas from a car or truck is hard, but from a boat or jet ski, it’s much easier. Jet skis don’t have a block to stop you from siphoning gas, and even if they did, you can take the seat off and get the gas that way.

A PWC can hold up to 20 gallons of gas, that is about two cars worth of gasoline!

Though I will give a point to the people who store a boat near full of gas as it will make for a great emergency backup gas supply to run a generator.

To see more about jet ski security and things you can do, go here!

5. Cuts Down On Waste

If you’re storing your jet ski full of gas during the winter, you still run the risk of that gas going bad. The longer the jet ski sits, the greater the chances of the gas going bad.

When it does go bad, you now have a lot of fuel to get rid of that many engines won’t like. At best, you’ll have plenty of gas to run your lawn mowers, but your cars and boats will not like it.

You can’t dump the gas either, it must be disposed of properly and by a professional. Gas vapors are no joke, and sucking it back out of your jet ski is dangerous!

As talked about in point 2, I rather have a little gas that goes bad and then add fresh fuel to dilute it. It’s easier to dilute a little bit of gas than to get rid of a lot of bad fuel.

What Should You Do?

At the end of the day, it’s more about personal preference and what is right for you.

There is at least one good point about storing a jet ski full of gas for emergency fuel supply, but overall, I think it’s not worth it.



I began working at a jet ski dealership in 2007, initially in the parts and service area. I then transitioned to the technician side before eventually joining the sales team in 2013. I've done it all! While in sales, I created this website in 2014 to assist others with their common questions about watercraft. I now manage this site full-time, where I answer common questions, offer advice, and assist others with their PWC needs.

I've owned several watercraft and continue to buy, sell, and repair them. Currently, keep my Sea-Doo Spark as my main PWC. Additionally, I have developed tools like a used watercraft value calculator, a pricing calculator, an hour calculator, and more to better assist my readers.


  1. I had always heard that keeping gas tanks 80% (ish) full in the off season helped to keep seals and other components “wet” so they didn’t dry out. Kinda like a cork in a wine bottle or running the dishwasher every once in a while. You don’t want those things going a long time without being used or the cork/seals dry out and then the first time you go to use them you have a huge (and costly) mess.

    • That’s a fair point, but I’ve never seen this be a huge problem. I’ve gotten jet skis out of crates that have been sitting for years with no gas in them and everything be fine. A lot of the problems I see are due to ethanol in gas, that is more likely to destroy seals and lines more than keeping them dry.


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