How to winterize a lawn mower

Allen Foster

Winterizing your lawn mower isn't a time-intensive or costly task. If you want to get a head start on spring prep, you can sharpen (or replace) the blade, change the air filter, and replace the spark plugs over the winter as well.

winterizing your lawn mower only involves a little more effort than the routine maintenance you perform throughout the season

You never know when it’s going to be that last mow of the season.

However, once the temperature starts hanging around 40 degrees Fahrenheit, a couple of weeks have gone by without noticeable grass growth, and the leaves are gone, it's time to think about winterizing your lawn mower.

Winterizing shouldn't be an afterthought. It's as important to your outdoor equipment as adding fuel — without it, your machine might not run. Also, it should not be something you dread doing because it is easier than preparing your lawn mower for that first cut of the season.

Is fuel stabilizer really necessary?

Although oxygen gives us life, it is also responsible for breaking down nearly every substance we know. This includes gasoline.

Gasoline that has been left in an engine for several months may cause problems that are only discovered when you finally try starting that engine. To protect fuel from oxidation (and the engine from the degrading fuel), you need to add a fuel stabilizer.

Even more important, after adding a stabilizer, you will want to start the engine and let it run for a few minutes so the stabilized fuel can work its way through the engine. A fuel stabilizer is inexpensive and some brands can protect your fuel and your engine for up to two years, so there's no reason not to use it. Also, a fuel stabilizer cannot "fix" bad fuel, so the sooner you use it, the better.

There are two important caveats regarding keeping fuel in your lawn mower during the off-season. First, if you have a walk-behind mower and you are planning on doing other tasks such as cleaning the deck, sharpening the blade, or just storing the lawn mower upright, you will want to drain the gasoline to avoid leaks and spills while working. Second, if you need to store your lawn mower inside of your home, you must drain out the fuel for safety purposes.

Should I change the oil?

If your lawn mower requires regular oil changes (not all do these days), then most experts agree it is better to change your lawn mower's oil at the end of the season so dirty oil isn't sitting in your lawn mower all winter long, aiding in corrosion and gumming up the works. The best strategy is to drain the oil from the mower, clean beneath the mower deck, then add fresh oil when all the underside maintenance has been completed.

Clean beneath your lawn mower deck

Grass clippings, mud, debris, animal waste, and more collect and coat the underside of your lawn mower deck during normal use. If left there over the winter, however, they can corrode your lawn mower. Before you put your lawn mower in storage, you need to thoroughly clean beneath the lawn mower deck.

If you have a walk-behind mower, this process will be much less messy if you first drain the fuel and oil. Additionally, for safety reasons, it is advisable to remove the spark plug. Lastly, whenever you are doing tasks near the blade, you will want to be wearing a pair of heavy-duty work gloves.

Since the grass clippings can be caked on like dried paste, certain tools can come in handy when cleaning the underside of a lawn mower deck. A narrow putty knife or a stiff scrub brush is best for removing those caked-on materials.

While some manufacturers are now including a port on the upper side of the mower deck to attach a hose for easy cleaning, it is not advisable to use a hose with a high-pressure nozzle or a pressure washer on your lawn mower because it can force water into areas where you do not want water to go.

After the underside of your mower deck is clean and dry, some individuals like to coat it with lawn mower underdeck spray, which helps protect your lawn mower and reduce debris buildup after operation.

What to do with the battery

If your lawn mower has a battery, you need to disconnect that battery and bring it inside to a dry, temperature-controlled space before storage, as extreme temperatures may shorten the lifespan of your battery. Additionally, you may want to charge the battery once or twice while in storage to keep it in optimum working condition. The best battery charger switches to maintenance mode when the battery is fully charged so you cannot overcharge it.

The best way to store your lawn mower

After adding a fuel stabilizer, changing the oil, cleaning under the deck, and removing the battery (if needed), you are ready to store your lawn mower for the winter.

Ideally, putting your mower in a garage, shed, or storage unit is best to keep it out of the elements. Storing your lawn mower in the basement is also an option, but the fuel needs to be removed and the unit cannot be positioned near any heat sources, such as a furnace, a water heater, or any appliance with a pilot light. The last and least desirable option is to purchase a lawn mower cover and shield your mower as best as you can from the elements when storing it outside.


Allen Foster is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.

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