When the last leaf falls and your mower sits idle for months, skipping winterization is one of the costliest mistakes a homeowner can make. Learning how to winterize a lawn mower for storage protects your investment and saves you from a frustrating spring startup that refuses to turn over.
Stale fuel gums up carburetors. Old oil corrodes engine bearings. Moisture rusts your deck and dulls freshly sharpened blades. None of these problems fix themselves over winter, and most of them cost real money to repair.
The good news is that winterizing a lawn mower takes about an hour and a handful of inexpensive supplies. Whether you own a push mower, riding mower, zero turn, or electric model, this guide walks through every step you need to prepare your machine for off-season storage in 2026.
Yes, you are supposed to winterize a lawn mower if it will sit unused for more than 30 days. Anyone who stores a gas-powered or electric mower through winter benefits from proper preparation, and the steps below cover exactly what to do.
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The best time to winterize your lawn mower is right after your final mow of the season, before the first hard frost hits your area. For most regions, that falls somewhere between late October and late November.
Do not wait until the dead of winter. Once temperatures drop below freezing, fuel changes consistency, oil thickens, and removing components like spark plugs and blades becomes much harder on cold metal.
A good rule of thumb is to schedule your winterization the same weekend you winterize your outdoor faucets. If you drain your hoses, it is time to drain and treat your mower.
Gather everything before you start so you are not running to the hardware store mid-project. Here is what you need to winterize a lawn mower:
Fuel stabilizer (such as Sta-Bil or Sea Foam)
SAE 30 or 10W-30 small engine oil
Replacement spark plug (matched to your engine model)
Air filter replacement or cleaning kit
Socket wrench set and spark plug socket
Oil drain pan and shop rags
WD-40 or light machine oil for lubrication
Putty knife or plastic scraper for deck cleaning
Battery tender or trickle charger (for riding mowers)
Breathable storage cover or tarp
Most of these items are reusable. A bottle of fuel stabilizer lasts multiple seasons, and a tube of machine oil covers several winterization cycles.
Follow these nine steps in order. Each one addresses a specific failure point that causes spring startup problems, and skipping any of them leaves your mower exposed.
The full process takes roughly 60 to 90 minutes for a push mower and 2 to 3 hours for a riding mower. Work in a well-ventilated area, ideally a garage or shed with the door open.
Always start with safety. Disconnect the spark plug boot before touching anything else on the engine. This prevents accidental starts while your hands are near the blade and belt.
For riding mowers and electric-start push mowers, disconnect the battery next. Remove the negative cable first, then the positive cable, and lift the battery out cleanly.
Clean the battery terminals with a wire brush and a dab of terminal cleaner. Corrosion builds up over the mowing season and will only get worse in storage.
Store the battery in a cool, dry location above freezing. Connect it to a battery tender or trickle charger to maintain charge without overcharging. A dead battery in spring is one of the most common winterization failures we see.
Fuel is the single biggest source of spring startup problems. Gasoline breaks down over time, forming gummy varnish deposits that clog carburetor jets and fuel lines. This is the step that matters most.
You have two options here, and both work if done correctly.
Option A: Add fuel stabilizer. Pour the recommended dose of stabilizer into a partially full tank. Use fresh fuel, not gas that has been sitting in a can since spring. Run the engine for 5 to 10 minutes so the treated fuel circulates through the entire system, reaching the carburetor and fuel lines.
Option B: Drain and run dry. Siphon or drain the tank completely, then start the engine and let it run until it stalls from fuel starvation. This empties the carburetor bowl and prevents residue buildup.
Which is better? It depends on who you ask. Manufacturer Briggs and Stratton recommends stabilizing with fresh fuel. Many experienced mechanics on lawncare forums swear by the drain-and-run-dry method. Both approaches work when executed properly, so pick one and commit to it.
One critical warning about ethanol fuel. Most pump gas contains up to 10 percent ethanol, which absorbs moisture from the air. Over winter, that moisture separates from the gasoline and settles in your carburetor, causing corrosion and starting problems. If you can find ethanol-free fuel in your area, use it for your final fill-up before storage.
Fuel stabilizer is not the same as octane booster. Stabilizer prevents chemical breakdown of stored gasoline. Octane booster raises combustion performance and does nothing to prevent fuel from going stale. Use the right product for the job.
Old oil contains combustion acids, moisture, and metal shavings from a season of use. Leaving contaminated oil in your engine over winter allows those acids to eat away at bearings and cylinder walls.
Run the engine for a few minutes before draining. Warm oil flows more freely and carries more contaminants out with it. Just do not run it hot enough to burn yourself on the exhaust.
Remove the drain plug and let the oil empty completely into your drain pan. Tilt a push mower carefully if it lacks a drain plug, and drain from the fill tube.
Refill with fresh SAE 30 or 10W-30 small engine oil. Check your owner's manual for the exact viscosity and capacity. Overfilling causes smoking and seal damage, so add slowly and check the dipstick.
Yes, you should change oil before storage, not after. The whole point is to remove contaminants before they have months to corrode internal parts.
A fouled spark plug is the second most common cause of spring startup failures, right behind fuel issues. Remove the plug with a spark plug socket and inspect the electrode.
If the plug is dark, sooty, or coated in carbon buildup, replace it. Spark plugs cost less than five dollars and take two minutes to swap. There is no good reason to reuse a worn plug.
If the electrode looks clean and the gap is correct, you can reuse it. Check the gap with a gapping tool against your manual's specification. Most small engine plugs run between 0.020 and 0.030 inches.
Thread the plug back in by hand first to avoid cross-threading, then tighten with the socket. Reattach the spark plug boot only after all other maintenance is complete.
A dirty air filter chokes the engine and reduces power. Winter is the perfect time to clean or replace it so you start spring with full airflow.
For paper filters, hold the filter up to a light source. If you cannot see light through the paper, replace it. Tapping it against a surface only removes surface dust, not embedded debris.
For foam filters, wash the element in warm soapy water, rinse thoroughly, and let it dry completely. Apply a few drops of filter oil and squeeze to distribute evenly before reinstalling.
Some mowers use a dual-element design with both paper and foam components. Service both halves for best results.
Grass clippings, dirt, and moisture trapped under the deck cause rust and corrosion over winter. A clean deck survives storage far better than a caked one.
Tilt the mower back on its handle (push mowers) or raise the deck to its highest position (riding mowers). Always tilt the mower with the spark plug facing up to prevent oil from flooding the cylinder or carburetor.
Scrape the deck with a putty knife or plastic scraper. Avoid metal tools that scratch the paint and create rust entry points.
Once the bulk of the debris is gone, hose the deck clean and let it dry thoroughly. Some owners spray a light coat of WD-40 or vegetable oil on the clean deck surface to repel moisture through winter.
Dull blades tear grass instead of cutting it cleanly, which leaves your lawn vulnerable to disease. Winter is the right time to sharpen, balance, or replace your blade.
Remove the blade with a wrench, using a block of wood to keep it from spinning. Mark the bottom side with a marker so you reinstall it facing the correct direction.
Sharpen with a bench grinder, metal file, or rotary tool. Follow the original bevel angle and remove equal material from both ends to maintain balance.
An unbalanced blade vibrates violently and damages the crankshaft over time. Check balance by balancing the blade on a nail or a blade balancer tool. If one side drops, grind a little more off the heavy side.
If your blade has significant nicks, cracks, or thin metal, replace it entirely. A new blade costs 15 to 30 dollars and is far cheaper than engine repairs from vibration damage.
Friction and moisture team up over winter to seize pivot points, cables, and linkages. A few minutes of lubrication prevents stiff controls and frozen components in spring.
Apply light machine oil or WD-40 to the following areas:
Wheel bearings and axle points
Blade engagement lever and pivot points
Throttle and choke linkages
Deck height adjustment mechanism
Steering linkages on riding mowers
Grease fittings on commercial and riding mowers
Work each lubricated part through its full range of motion to distribute oil evenly. Wipe away excess so it does not attract dust and grime.
For mowers with grease fittings, use a grease gun to pump fresh grease until you see clean grease pushing out the seals. This pushes out old, contaminated grease along with any water trapped inside.
The final step gets your mower into safe storage position and protects it from dust, moisture, and pests.
Check tire pressure on riding mowers and inflate to the specification in your manual. Underinflated tires develop flat spots over months of sitting in one position.
For riding mowers with hydraulic systems, check the hydro oil or transmission fluid level. Top off if needed and inspect lines for leaks or cracking.
Cover the mower with a breathable cover or tarp. Avoid plastic tarps that trap moisture and promote condensation and rust underneath.
Store the mower in a dry, climate-controlled space if possible. A garage, shed, or basement works well. Keep it off bare concrete if you can, since concrete draws moisture.
Electric mowers need a different winterization process since they have no fuel, oil, or spark plugs. The focus shifts entirely to the battery and electrical components.
Remove the battery and store it indoors at room temperature. Lithium-ion batteries degrade faster in freezing temperatures and can lose capacity permanently if stored below 32 degrees Fahrenheit.
Charge the battery to roughly 50 percent before storage. Storing a lithium battery at full charge stresses the cells, while storing it empty can trigger a protective shutdown that requires professional reset.
Clean the deck and blade the same way you would on a gas mower. Remove grass buildup, dry thoroughly, and apply a light coat of oil to the blade and deck surface.
Inspect the power cord on corded models for nicks, cuts, or exposed wire. Replace damaged cords before next season rather than risking electrical shock.
Store the mower upright or flat per manufacturer instructions. Some electric mowers have specific storage positions that protect internal components from stress damage.
Even experienced homeowners make errors that cost them come spring. Here are the most common winterization mistakes we see:
Leaving old fuel untreated. This is the number one cause of spring startup failure. Stale fuel turns to varnish and clogs carburetor jets.
Skipping the oil change. Acidic old oil corrodes bearings and cylinder walls over months of contact.
Storing the battery on cold concrete. Cold drains batteries and concrete can accelerate discharge. Use a tender indoors.
Using a plastic tarp for a cover. Plastic traps moisture and causes more rust than leaving the mower uncovered in a dry garage.
Reinstalling a dull or unbalanced blade. Vibration from an unbalanced blade damages crankshaft bearings over time.
Starting the mower periodically in storage. Running the engine briefly draws moisture into the oil without burning it off, doing more harm than good.
Avoid these pitfalls and your spring startup will be smooth on the first pull.
Storage location matters as much as the winterization steps themselves. A properly prepped mower still suffers in the wrong environment.
The ideal storage spot is a dry, enclosed garage or shed with stable temperatures above freezing. Avoid locations with extreme temperature swings that cause condensation inside the engine.
If garage storage is not an option, a covered carport or sheltered area works as a second choice. Use a breathable, waterproof cover and elevate the mower off the ground on blocks or a pallet.
Storing a lawn mower outside for winter is possible but risky. If you must, build a raised platform, use a high-quality breathable cover secured against wind, and check periodically for moisture or pest intrusion. Mice love to nest in engine shrouds and chew wiring.
Never store a mower with fuel near a water heater, furnace, or any ignition source. Even stabilized gasoline is flammable and should be treated with respect.
To prepare your lawn mower for winter storage, stabilize or drain the fuel, change the engine oil, replace the spark plug, clean or replace the air filter, scrape the under deck, sharpen the blade, lubricate moving parts, remove and tend the battery, and store the mower in a dry location with a breathable cover.
Running the mower dry is one accepted method. Siphon the tank, then start the engine until it stalls to empty the carburetor. The alternative is adding fuel stabilizer to fresh fuel and running the engine for 5 to 10 minutes to circulate it. Both methods work when done correctly.
You should not leave old, contaminated oil in your mower over winter. Used oil contains combustion acids and moisture that corrode engine bearings during months of storage. Change the oil with fresh SAE 30 or 10W-30 before storing.
Fuel treated with a quality stabilizer stays fresh for 12 to 24 months when stored in a sealed tank. For seasonal storage of 4 to 6 months over winter, stabilized fuel performs reliably as long as you use fresh gasoline and run the engine to circulate the treated fuel.
No, you should not start your mower periodically during winter storage. Brief runs do not warm the engine enough to burn off condensation, so moisture accumulates in the oil and exhaust system. Leave the mower dormant until spring.
Gas-powered mowers can tolerate freezing temperatures in storage, but batteries should be kept above 32 degrees Fahrenheit. Electric mower batteries degrade permanently if stored below freezing. Store lithium-ion batteries indoors at room temperature for best results.
To store a lawn mower outside for winter, elevate it on a pallet or platform to keep it off wet ground, cover it with a breathable waterproof cover, secure the cover against wind, and check periodically for moisture or pest intrusion. Stabilize the fuel and remove the battery for indoor storage.
Fuel stabilizer prevents gasoline from breaking down and forming gum and varnish during storage. Octane booster raises the combustion rating of fuel for performance but does nothing to prevent fuel from going stale. Use stabilizer for storage, not octane booster.
Knowing how to winterize a lawn mower for storage is the difference between a mower that fires up on the first pull in spring and one that ends up at the repair shop. Stabilize the fuel, change the oil, clean the deck, sharpen the blade, and store it somewhere dry.
The whole job takes about an hour for a push mower and an afternoon for a riding model. Do it before the first hard frost, while the engine is still warm from your final mow and the weather cooperates.
Your mower works hard all summer. Give it the off-season care it deserves, and it will be ready to go when the grass starts growing again in 2026.