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Should I Store My Lawn Mower with Gas?

By Jeff Mercer · Updated September 24, 2026 · 3 min read
Should I Store My Lawn Mower with Gas?
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Hey there, it’s your pal Jeff here. I’m here to talk about a question that I’m sure we’ve all asked ourselves at some point: Should I store my lawn mower with gas in the tank?

I’ll admit, I’ve made some mistakes in my time when it comes to storing my mower, so let me share what I’ve learned with you.

Why You Shouldn’t Leave Gas in Mower Over Winter

First off, let’s talk about why you shouldn’t leave gas in your mower when storing it for the winter (or any extended period of time).

Gasoline is made up of a bunch of different chemicals, and over time, these chemicals start to break down and form gunk and contaminants.

This process is accelerated by heat, moisture, and air exposure, so if you’ve got a tank full of gas sitting in your garage all winter, it’s likely to go bad faster than a tank that’s been emptied and refilled with fresh gas.

Leaving old gas in your mower when storing it can cause all kinds of problems, including engine damage, poor performance, and difficulty starting.

And if you’re not using your mower during the winter months, it’s likely that the gas will go stale before you even have a chance to use it again.

What to Do with Gas in Mower When Storing

So, what should you do with the gas in your mower when storing it? Here are a few options:

  1. Drain the gas out of the tank and refill it with fresh, high-quality gas before storing your mower.
  2. Add a fuel stabilizer to the gas to help extend its shelf life.
  3. Store your mower in a cool, dry place to help prevent the gas from going bad.

FAQ

Should I Leave Gas in Mower When Storing?

It’s generally not a good idea to leave gas in your mower when storing it for an extended period of time.

Gas starts to go bad after about three to six months, and leaving old gas in your mower when storing it can cause all kinds of

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problems, including engine damage, poor performance, and difficulty starting. If you need to store your mower, it’s best to drain the gas out of the tank and refill it with fresh, high-quality gas before storing it.

How Do I Store My Mower for the Winter?

To store your mower for the winter, follow these steps:

  • Drain the gas out of the tank and refill it with fresh, high-quality gas.
  • Add a fuel stabilizer to the gas to help extend its shelf life.
  • Clean the mower thoroughly, including the blade, air filter, and undercarriage.
  • Remove the spark plug and squirt a teaspoon of oil into the cylinder. Turn the flywheel slowly to distribute the oil.
  • Re-install the spark plug.
  • Store your mower in a cool, dry place, away from extreme temperatures and moisture.

Conclusion: Don’t Fuel Your Mower’s Winter Blues

In conclusion, it’s important to pay attention to the age of the gas in your mower when storing it for the winter (or any extended period of time).

Gas starts to go bad after about three to six months, and using old gas can cause all kinds of problems, including engine damage, poor performance, and difficulty starting. If you’ve got old gas in your tank and you’re not sure if it’s still good, it’s best to drain it out of the tank and refill it with fresh, high-quality gas.

And if you need to store your mower for the winter, make sure to follow the tips above to help extend the shelf life of the gas.

So, don’t fuel your mower’s winter blues – keep that gas fresh, and you’ll have a smooth, hassle-free winter. Happy mowing (or shoveling)!

Before you start the repairI'm a homeowner who does his own small-engine work, not a certified technician. Before any repair, pull the spark plug wire and let the engine cool. Anything involving blades under a raised machine, fuel system leaks or transmission internals — if you're not sure, have a dealer or small-engine shop look at it.
Jeff Mercer

Written by

Jeff Mercer

Hi, I'm Jeff. I look after about an acre of lawn, a riding mower, a zero-turn, a push mower that is older than some of my neighbours' cars, and a snowblower that only ever breaks the night before a storm. Doing my own repairs started as a way to save on dealer labour and turned into the part of yard work I actually enjoy.

GardenTooly is where I answer the questions people type into a search bar while standing next to a machine that won't behave: why the deck shakes, why the mower dies when it warms up, whether a bent blade shaft can be straightened, what the difference between two transmissions really means for you, and which fuel additive is worth the shelf space.

I'm not a certified small-engine technician and I don't sell equipment. Where I've done a job myself, I say so. Where an answer comes from the owner's manual, a service bulletin or a mechanic who knows more than me, I say that instead — and anything involving blades, fuel, jacked-up machines or a hydrostatic transmission gets a plain "take it to a shop" when that's the right call.

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