How Do I Prep My Lawn Mower for Winter Storage?

Article Posted By: Craig Allen

of Senior Editor, The Home Depot Blog

A lawn mower covered in snow

Hint: This is NOT a good way to store your lawn mower in the winter, even if you drain the gas tank.

How do I prep my lawn mower for winter storage?

A lot of homeowners aren’t sure how to prepare their mowers for winter storage, despite using their lawn mowers almost every week throughout the spring and summer. We have an idea that we need to do something special to prepare for winter storage, but aren’t sure exactly what needs to happen. For example, what should we do about the gasoline in the tank, are there special storage instructions, etc.?

Do I need to drain the fuel?

A Home Depot Community member who posts under the handle ToolBoxHero asked about that on our Community Forums. He wondered if his time-consuming process of preparing his mower for the winter was worth the effort:

“I was curious about draining the gas out my lawn mower, riding lawnmower or snow blower at the end of the season. I have heard horror stories about people leaving the gasoline in the tank and having all kinds of trouble starting it the following year, and having to take the lawn mower or snow blower to a repair shop to have it fixed. I have chosen to drain all of the gas out of my riding mower and push mower this year– siphoning as much as possible, and then running the engine until it stopped, followed by draining out the fuel filter.

“Is draining the fuel from the mower the best way to do this? Or can I just add a fuel stabilizer to the gas left in the tank and call it a day?”

A fuel stabilizer might be all you need

Sta-Bil Fuel StabilizerAs Community associate LawnRanger explained, it’s the addition of ethanol to gasoline that can cause problems for lawn mower storage. Gas shouldn’t sit in a gas can or gas tank more than about three months. After that, the ethanol starts to break down, releasing water into the gasoline, and the fuel loses its ability to combust. So, draining the gas from your lawn mower isn’t a bad thing to do before it takes its winter break. But that might not be completely necessary.

RicksPicks, another of our Home Depot how-to experts, said that if you don’t want to drain the tank, then keep it full to the brim, but with a dose of stabilizer in the tank. He told of how he prepared a gasoline powered chipper for a year’s storage:

“We cleaned it off, covered it up, until the next time we planned on using it, I filled up the gas tank with gas, treated with a fuel stabilizer called Sta-Bil and ran the engine for a few minutes. After about a year of not being used, I uncovered the chipper, primed it and on the second pull, it started right up!  It coughed a couple of times and belched a little smoke, but ran like a champ after that initial start.

“I think the key is to be sure that the tank is completely full of fuel so that there is no room for moisture to accumulate. As long as you have a fuel stabilizer in the gas lines and the tank is full, you are good to go.”

RicksPicks mentions using Sta-Bil as the fuel stabilizer. But what if you didn’t add Sta-Bil, and now you have a tank of gasoline that’s broken down? Give Mechanic in a Bottle a try. Take a look at a short article and video demonstration of Mechanic in a Bottle. It can rescue old gas that’s broken down. It also works well as a stabilizer to prevent the fuel from going bad in the first place.

For long-term storage, do this:

One of the good things about our online Forums is that, not only will you get expert advice from our Home Depot associates, but you’ll often also get some good recommendations from other readers. Forums member GrueMaster gave us his procedure for winterizing gasoline powered equipment for a season in more harsh conditions, or for long-term storage. It’s kind of old school, but this will keep your small engine running for a long time. And if you have the time, it couldn’t hurt to do this even for short-term winterization.

“I have been told by several small engine repair mechanics to drain the tank, then run the engine until it dies (some fuel will remain in the carburetor unless you do).

“The next step is to remove the spark plug and put about a cap full of oil in the hole. For mixed-fuel engines use the oil mix and about half a cap, for regular engines that just take gasoline, use 10W-30 oil. After adding the oil, replace the plug (without reconnecting the wire) and pull the starter cord gently a couple of times. This helps lubricate the engine and keeps condensation from forming, which will cause serious trouble later.

“I have a roto-tiller that sat for four years, and it fired up without any problems because I stored it this way.”

The takeaway

If you’re planning on storing your lawn mower, snow blower, chainsaw, etc., for a long time, you might want to consider taking the time to drain the fuel. But if it’s just for a few months, then you can probably get away with topping off the tank and adding a fuel stabilizer. Don’t forget to add some stabilizer to the gas in your gas can, too.

Shop The Home Depot’s Outdoor Power Equipment page for lawn mowers, leaf blowers, snow blowers and more, and everything you need to maintain them.

Lawn mower photo © elPadawan, used under Creative Commons license

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