Should You Store A Lawnmower With A Full Tank Of Gas?

You’ve probably heard differing views about whether you should top up your mower with fuel before storing it between mowing sessions or for a longer period of time, like over the winter months. So what’s the answer? Should you store the lawnmower with a full tank of gas and how does this affect your safety or the performance of your engine? Does it even matter?

If you store your lawnmower in the basement or a garage attached to your property, always drain the fuel tank before putting it away no matter how long you’re storing it for. When stored in a separate garage or shed for more than a month, a mower should either be kept with a full tank of stabilized gas or drained completely. 

This article considers the pros and cons of storing a mower fully gassed up as well as providing some crucial safety tips. So, if you’ve ever pondered this seemingly trivial yet important question, grab a cup of coffee and read on!

Is It Safer To Store My Lawnmower Full Or Empty?

The answer to this depends largely on where you store your mower. For storage areas within your living space, such as a basement or a garage that’s integral to your house, you will need to make sure it’s been drained of gas. This applies even if just putting it away for a short time between mowing during the summer.

The reason for this is that fumes from the gasoline can enter your home and result in a risk of an explosion. There are many sources of ignition in the typical home including light switches, furnace pilot lights, electrical appliances, and so on. Any one of these could easily ignite the fumes from the gas in a lawnmower so it’s just not worth the risk of not emptying it.

If you have a separate shed or garage to store your machine in then the choice becomes less clear and you may need to turn to the instructions in your owner’s manual as a guide to what’s best for your particular model. 

If you don’t have that available, then as a general rule of thumb, storing your mower full of gas in a shed or standalone garage has quite a few benefits that I’ll go into below, and is generally safe to do as long as you follow a few precautions.

Safely Storing Lawnmowers With A Full Tank

If you’re storing your mower full of gas, safety should always be your top priority. Here are some essential safety tips and precautions to keep in mind:

Proper ventilation: Lawnmower fuel tanks are often vented to make sure pressure doesn’t build up inside them, so make sure your storage area is a well-ventilated area to avoid the buildup of dangerous fumes. 

Store away from ignition sources: Avoid storing a full mower near sources of heat or flame, as gasoline vapors are highly flammable.

Secure storage: Ensure that your lawnmower is stored in a secure location, away from children and pets. This not only reduces the risk of accidents but also helps prevent theft.

Use fuel stabilizers: If you decide to store your lawnmower with a full tank of gas, add a fuel stabilizer to the gasoline before filling the tank. This can help prolong the life of the gas and prevent engine damage.

If you are wondering how long you can store your lawnmower with fuel in it, you can read about that topic in more detail here

Now let’s delve into the advantages and disadvantages of storing your mower with a tank full of gasoline.

Why Store A Mower With A Tank Full Of Gas?

First, let’s look at the reasons many experts and manufacturers recommend storing your lawnmower with a tankful of stabilized gas, particularly when this is for a longer period of time. 

One major benefit is that this practice can help prevent condensation from forming inside the fuel tank. Condensation can lead to water mixing with the gasoline, which, in turn, can cause rust, corrosion, or other damage to the engine and carburetor.

It also means that the fuel system and engine parts are protected by the stabilizer additives contained in the gas, as long as you run the mower for a few minutes after adding the stabilizer to the fuel tank.

Another advantage of storing it this way is the convenience factor. With a full tank, you’re ready to go as soon as the weather permits at the start of the season without a trip to the gas station.

Always add a fuel stabilizer when storing your mower for more than a month. In fact, it’s a good idea to use these products all the time. The additives can keep the gasoline fresh for up to 12 months and protect the engine from gum, varnish, and rust, all of which can result from stale fuel.

Why You Shouldn’t Store Your Mower With A Full Fuel Tank

On the other hand, there are some valid arguments against storing your lawnmower full of fuel. The primary concern is safety. 

Storing gasoline in a mower’s fuel tank can pose a fire risk through the venting of fumes as it’s not designed for long-term storage unlike a gas can made for the job.

Fuel degradation is another issue that can’t be ignored. Gasoline begins to break down after a month or so, particularly fuel with added ethanol, which can lead to the formation of gum and varnish inside the engine. 

This can cause your lawnmower to run poorly or not start at all when you need it next season.

Finally, there’s the possibility of fuel leaks and spills. A lawnmower that’s not in use can still experience leaks, either due to damage or normal wear and tear. Always check your mower over before storing it for a long time to make sure.

If you decide to drain the contents of your mower’s fuel tank into a gas can, you will still have to store it safely. You can read more on how to do that here


In conclusion, the choice of whether to store your lawnmower with a full tank of gas depends on where you are going to store it, how long for, and what the owner’s manual recommends.

Whatever you decide, it pays to use fuel treated with a suitable stabilizer product even if you’re running the mower dry before winterizing it.

Peter Toth

Hi! I'm Peter, the owner of BackyardGadget. Working around the house has always been a big part of my life. I've created this site to share my experience, and to help people choose the right tools for the job. Thank you for stopping by!

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