Should I Run My Lawn Mower Out of Gas Before Winter

Quick Overview

• Yes, running your mower out of gas before winter is a smart move. It’s simple and it works.
• A fuel stabilizer also works well. It just takes a bit more planning.
• Doing nothing is the risky choice. Old gas gums up the carburetor fast.
• I’ve tested both methods for years. Running it dry wins for most homeowners.
• Either way, don’t skip winter storage steps like a battery check and blade cleaning.

Should I Run My Lawn Mower Out of Gas Before Winter?

Yes. Running your mower out of gas before winter is one of the easiest ways to protect the engine. I’ve done it for years, on three different mowers, in two different states. It works.

Picture a garage in late October in Minnesota. The air smells like fallen leaves. My neighbor Dave leaned on his rake and told me, “Always drain the tank before winter, or you’ll be sorry.” He wasn’t wrong, but he wasn’t quite right either. There’s more to it than draining a tank.

This guide is for anyone who owns a gas mower and doesn’t want a nasty surprise in April. Maybe you’re new to lawn care. Maybe your mower struggled to start last spring and you’re tired of it. Either way, you’re in the right place.

I remember the first time a mower let me down in spring. It was a Craftsman, a hand-me-down from my father-in-law. I pulled that cord more than twenty times on a cold March morning. My arm ached. My patience ran out fast. When I finally got it to a repair shop, the guy took one whiff of the tank and just shook his head. “Stale gas,” he said, like he’d seen it a thousand times. He probably had.

That morning taught me more than any manual ever did. Since then, I’ve tested different approaches, mower after mower, season after season. Some worked better than others. Some cost me money I didn’t need to spend. This guide is what I wish someone had told me back in that Ohio driveway.

I’ll walk you through running your mower out of gas the right way. I’ll also cover the fuel stabilizer method, and what happens if you skip both. Spoiler: skipping both is the one thing I don’t recommend.

Why This Question Trips Up So Many Homeowners

This question trips people up because they get conflicting advice from every direction. One neighbor says drain it. Another says use stabilizer. A third says it doesn’t matter at all.

The truth is simpler than it sounds. Gas breaks down over time. Left sitting in a mower all winter, it turns into a sticky mess. That mess clogs small parts inside the carburetor. Both methods below prevent that. Doing nothing does not.

The Old-School Advice Everyone Repeats

“Just run it dry” is advice that’s been passed down for decades. Grandpas, uncles, and hardware store clerks all say it. And for good reason. It’s free, it’s simple, and it works.

But here’s what most people leave out. Running it dry doesn’t remove every drop of gas. Some fuel stays in the lines and the carburetor bowl. That leftover fuel can still go stale if you wait long enough before your first spring mow.

What Actually Happens to Gas Sitting All Winter

Gas sitting all winter starts to break down within 30 to 60 days. Most pump gas today contains ethanol, an alcohol added to reduce emissions. Ethanol absorbs moisture from the air.

That moisture separates from the gasoline over time. This is called phase separation. Once it happens, you get a layer of water and ethanol sitting below a layer of gas. Neither layer runs an engine well.

The result is stale gas. It smells sour, almost like nail polish remover. If you’ve ever caught that smell coming from an old gas can, you know exactly what I mean.

I once opened a gas can that had been sitting in my Ohio garage for over a year. The smell hit me before I even got the cap fully off. It wasn’t the usual gasoline smell either. It was sharper, almost sweet in a bad way. That’s the smell of gas that’s already turned. Once you smell it once, you never forget it.

Most gas stations sell fuel with up to 10 percent ethanol, sometimes labeled E10 on the pump. A few stations sell ethanol-free gas, usually marked clearly and priced a bit higher. If you have access to ethanol-free gas, it holds up longer in storage. But even that gas isn’t immune to breaking down eventually.

The small engine in your mower is more sensitive to this than a car engine. Cars run their fuel systems constantly, so gas rarely sits long enough to separate. A mower parked all winter gives that gas plenty of time to go bad.

Running It Dry vs. Using a Fuel Stabilizer

Running it dry and using a fuel stabilizer both protect your mower from stale gas damage. They just go about it in different ways. One removes the fuel. The other treats it so it won’t break down.

I’ve used both methods on different mowers over the years. My old Craftsman got the run-dry treatment. My Toro gets stabilizer every fall. Both mowers started on the first pull the following spring.

How to Run a Mower Out of Gas the Right Way

The right way to run a mower out of gas is to stop adding fuel a few weeks before your last mow, then let the engine use up what’s left. Here’s how I do it each October.

1. Stop filling the tank once you’re down to about a quarter tank.
2. Keep mowing as normal until the engine starts to sputter.
3. Let it run at idle for a minute once it sputters. This clears fuel from the lines.
4. Pull the cord a few times after it stalls, just to be sure.
5. Check the fuel filter and drain any remaining drops from the bowl if your mower has a drain screw.

This process takes no extra time. You’re just planning your last few mows around your fuel level. That’s the whole trick.

One downside: you can’t always predict exactly when the tank will run dry. Some engines sputter for a while before they fully stop. That’s normal. Just let it happen.

The first time I tried this, I got impatient. The engine sputtered, caught again, sputtered some more. I almost gave up and shut it off early. I’m glad I didn’t. It took another minute or two of stop-and-start running before the tank was truly empty. Patience matters here more than people expect.

I’ve also learned to do this on a day when I don’t mind the extra noise. A sputtering engine isn’t quiet. My wife has asked more than once why the mower sounds like it’s dying in the driveway. I just tell her that’s the point.

One thing worth mentioning: don’t try to speed this up by tipping the mower to drain fuel through the cap. That’s messy, it wastes gas, and it can damage the engine if oil shifts into the wrong chamber. Just let the engine burn through what’s left on its own.

How Fuel Stabilizer Works Instead

Fuel stabilizer works by slowing down the chemical breakdown of gasoline. You add it straight to the tank, then run the engine for a few minutes so it circulates through the whole fuel system.

Brands like Sta-Bil and Briggs & Stratton make stabilizer that claims to keep gas fresh for up to two years. I’ve tested it for one winter at a time, and it’s held up every time on my Toro.

Here’s how to use it:

1. Fill the tank most of the way. A fuller tank means less air space for condensation.
2. Add stabilizer using the ratio on the bottle. Most call for about 1 ounce per gallon.
3. Run the mower for 5 to 10 minutes so treated gas reaches the carburetor.
4. Store the mower with that treated gas still in the tank.

The upside is you don’t have to time your last mow around an empty tank. The downside is cost. A bottle runs $8 to $12, and you have to remember to buy it every fall.

My Toro sits in a small shed behind my garage. Every October, I add stabilizer while the tank is still mostly full from my last mow of the season. The whole process takes about ten minutes, including the short run time to circulate the treated gas.

I’ll admit, I forgot one year. I found the bottle sitting on my workbench in November, long after the mower was already tucked away for the season. That gas sat untreated all winter. Come spring, the mower started, but it ran rough for the first few minutes. Lesson learned. If you’re going the stabilizer route, treat the tank before you park the mower for good, not after.

One more tip. Shake the stabilizer bottle before you pour it in. The active ingredients can settle at the bottom, and a weak mix won’t protect your fuel as well as a properly mixed one.

Compression Table Comparing Both Methods

What Happens If You Do Nothing at All

If you do nothing at all, the gas in your tank will likely go stale by spring. This is the outcome I’ve seen cause the most frustrating mower problems. It’s also the most common mistake homeowners make.

I learned this the hard way with my first mower, a basic Craftsman I bought used. I left a half-full tank sitting all winter in an unheated Ohio garage. Come April, it wouldn’t start. Not even close.

Stale Gas and Carburetor Problems

Stale gas causes carburetor problems because the gummy residue left behind clogs the tiny passages that control fuel flow. The carburetor is where air and fuel mix before combustion. Those passages are smaller than a pencil lead in some spots.

Once they’re clogged, fuel can’t flow correctly. The engine either won’t start, or it starts and dies right away. That sour smell from stale gas is often your first clue something’s wrong before you even try the pull cord.

Real Repair Costs I’ve Seen

Real repair costs for stale-gas carburetor problems typically run $50 to $150 at a small engine repair shop. A basic cleaning with carburetor cleaner and a rebuild kit runs on the lower end. A full carburetor replacement runs higher.

My neighbor Dave, the one with the rake, paid $95 to have his Honda mower’s carburetor cleaned two springs ago. He told me afterward, with a laugh, that stabilizer would have cost him three dollars.

I’ve cleaned carburetors myself with cleaner spray and a small wire, and it’s doable for a confident DIYer. But it takes patience, and it’s messy work. Most people would rather pay the shop or just avoid the problem in the first place.

Beyond the repair bill, there’s the lost time. Spring is when grass grows fastest. A mower stuck at the shop for a week means either paying a neighbor kid to mow, letting the lawn get shaggy, or borrowing a mower from someone down the street. None of those options feel great when you just want to get your Saturday chores done.

I’ve also seen cases where stale gas causes more than a carburetor problem. If it sits long enough, it can gum up the fuel line itself, or leave deposits on the intake valve. Those repairs cost more and take longer. It’s rare, but I’ve heard about it from more than one small engine repair shop owner over the years.

Storing Your Mower for Winter (Step by Step)

Storing your mower for winter takes more than just handling the fuel. A few extra steps protect the blade, the battery, and the engine itself. None of these take more than a few minutes.

Cleaning the Deck and Blade

Cleaning the deck and blade removes grass clippings that trap moisture against the metal. That trapped moisture causes rust over the winter months.

Flip the mower on its side, with the air filter facing up so oil doesn’t leak into it. Scrape off caked grass with a putty knife or stiff brush. A garden hose works for lighter debris, but let everything dry fully before storage.

Check the blade for nicks or dullness while you’re under there. Winter is a good time to sharpen it or swap it out, since you won’t need it again until spring.

I keep a spare blade on a shelf in my garage for exactly this reason. Swapping a dull blade takes ten minutes with a socket wrench, and it means my first mow in spring cuts clean instead of tearing the grass. A dull blade actually stresses your lawn, leaving ragged, brown-tipped edges on every blade of grass it touches.

While you’re cleaning, take a look at the underside of the deck for rust spots. A light coat of spray lubricant or a rust-inhibiting spray can help protect bare metal spots through a damp winter.

Battery and Spark Plug Care

Battery and spark plug care matters most if you own a riding mower or a battery-powered model. For riding mowers, either remove the battery and store it somewhere above freezing, or hook it to a trickle charger.

A dead battery is one of the most common spring headaches I hear about from neighbors. Cold temperatures drain battery power fast, especially in places like Minnesota or Wisconsin.

For the spark plug, pull it out and check the tip. If it’s black and crusty, replace it. A fresh spark plug costs about $5 and makes spring starting much easier.

I replace mine every fall now, whether it looks bad or not. It’s cheap insurance. A worn spark plug is one of the most common reasons a mower cranks but won’t fire up in spring, right alongside stale gas.

For push mowers with a battery-powered starter, check the battery connections for corrosion before storing it. A little white, crusty buildup on the terminals can prevent a good connection. A wire brush and a few minutes of scrubbing usually clears it right up.

Where and How to Store It

Where and how to store your mower matters more than most people think. A dry, covered space like a garage or shed is ideal. Avoid leaving it outside under a tarp if you can help it, since moisture still gets in.

If your garage isn’t heated, that’s fine. Cold temperatures alone don’t damage a mower. It’s moisture and stale gas that cause the real problems.

Compression Table

Regional Differences That Actually Matter

Regional differences actually matter because winter length and humidity change how much fuel and moisture risk your mower faces. A mower sitting in a Minnesota garage for five months faces different conditions than one sitting in a Georgia carport for six weeks.

Cold Winters (Minnesota, Wisconsin, the Midwest)

Cold winters in places like Minnesota, Wisconsin, and the broader Midwest mean your mower could sit unused for five or six months. That’s a long stretch for gas to break down, so I’d lean toward whichever method you’re more consistent about doing right.

I run my mower dry every year in these conditions, mostly because I know I’ll forget to check on stabilizer levels by March. Pick whichever method fits how much you’ll actually follow through.

A friend of mine in Wisconsin stores his riding mower in an unheated pole barn from late October through early April. That’s nearly half a year of sitting still. He swears by stabilizer, mostly because his riding mower’s tank is too large to comfortably run dry without wasting a lot of usable fuel. For a big tank like that, stabilizer often makes more practical sense.

Whichever method you choose in a cold climate, don’t skip the battery step either. I’ve seen more dead riding mower batteries in Midwest garages than almost any other winter mower problem. Cold saps battery charge fast, even faster than most people expect.

Mild Winters (Southeast, Southern California)

Mild winters in the Southeast or Southern California mean shorter storage periods, sometimes just six to eight weeks. Some homeowners in Georgia or Florida even mow lightly through winter if grass keeps growing.

In these areas, stale gas is less of a worry since the mower doesn’t sit as long. Either method still helps, but the stakes are lower if you skip a step here or there.

A cousin of mine mows a small yard in a Georgia carport almost year-round. His grass barely slows down, even in January. For him, the whole winter storage question is less about fuel and more about keeping the deck clean and the blade sharp, since the mower rarely gets a real break.

If you live somewhere with mild winters, humidity can still be a factor. Coastal areas in the Southeast see plenty of damp air, which can lead to rust even if fuel isn’t your main concern. A dry storage spot still matters, even where winters are short.

Mowers That Sit Unused for Months vs. Year-Round Use

Mowers that sit unused for months need fuel treatment far more than mowers used year-round. If your mower barely stops running, like in parts of Southern California, stale gas rarely becomes an issue since fuel gets replaced often.

The longer the mower sits, the more this decision matters. A five-month gap in Minnesota is a real risk. A six-week gap in Georgia is a much smaller one.

Common Mistakes People Make Before Winter

Common mistakes people make before winter usually come down to skipping small steps that seem unimportant. I’ve made both of these myself, so I say this from experience, not judgment.

Forgetting the Fuel Filter

Forgetting the fuel filter is an easy mistake, since it’s a small part tucked into the fuel line. Stale gas particles can clog it even if you handled the tank correctly.

Check it each spring before your first mow. A cheap replacement filter costs about $3 to $6 and takes just a few minutes to swap.

Storing It With a Full Tank and No Stabilizer

Storing it with a full tank and no stabilizer is the mistake I see most often. People think a full tank is safer than a partial one, but without stabilizer, that full tank just means more stale gas come spring.

If you’re not going to run the tank dry, always add stabilizer. Never leave raw pump gas sitting untreated for months.

I’ve seen this mistake play out with a neighbor’s Husqvarna push mower. He topped off the tank in September, right before the growing season slowed down, and never touched it again until the following May. By the time he pulled the cord, the engine wouldn’t even sputter. He ended up replacing the carburetor entirely, a repair that cost him more than a bottle of stabilizer would have over ten winters combined.

It’s an easy trap to fall into, especially if your last mow of the season happens to land on a full tank. The fix takes two minutes. Just don’t skip it.

Pros and Cons Table

My Final Recommendation

After years of testing both methods, running your mower out of gas before winter is my top pick for most homeowners. It costs nothing, and it’s hard to mess up once you get the timing down.

That said, I don’t think stabilizer is a bad choice at all. If you’d rather not plan your last mow around an empty tank, stabilizer works just as well. I use it myself on my Toro because I like having a full tank ready to go in April.

Whatever you choose, don’t skip it. Dave’s $95 repair bill is proof enough for me. A few minutes in October saves a frustrating morning in spring, standing over a mower that won’t start, wondering where you went wrong.

Frequently Asked Questions

Should I run my lawn mower out of gas before winter?

Yes. Running it out of gas before winter prevents stale, ethanol-heavy gasoline from clogging your carburetor. It’s free and effective when done correctly.

How long can gas sit in a mower before it goes bad?

Gas typically starts breaking down within 30 to 60 days, especially gas with ethanol. In cold, humid garages, it can go bad even faster.

Is fuel stabilizer better than running the tank dry?

Neither is strictly better. Fuel stabilizer saves you from timing your last mow, while running it dry costs nothing. Both prevent stale gas problems well.

What happens if I leave gas in my mower all winter without stabilizer?

The gas will likely go stale, causing gummy residue to clog your carburetor. This often leads to hard starting or a $50 to $150 repair bill.

Can I just add fresh gas in spring instead of dealing with old gas?

Adding fresh gas to a tank with stale gas already in it doesn’t fix the problem. Old gas that’s already broken down will still clog the carburetor. Drain it fully before adding fresh gas.

Do I need to winterize a battery-powered mower the same way?

No. Battery-powered mowers don’t need fuel treatment at all. Just store the battery indoors at room temperature and avoid letting it sit at a full or empty charge for months.