How to Winterize Your Lawn Mower: A Complete Guide for Cold Weather Storage

Getting your winter lawn mower prep right can mean the difference between a smooth spring startup and hours of frustration come April. After months of faithful service cutting your grass, your mower deserves proper care before its winter hibernation.

Most homeowners make the mistake of simply wheeling their mower into the garage and forgetting about it until spring. That’s a recipe for rust, fuel problems, and expensive repairs. The good news? Learning how to winterize your lawn mower takes less than two hours and costs almost nothing.

Why Winter Lawn Mower Storage Matters

Cold weather wreaks havoc on small engines. Moisture causes rust, old fuel gums up carburetors, and dull blades sit deteriorating for months. Skip the prep work now, and you’ll pay for it later with costly repairs or replacement.

When you winterize your lawn mower properly, you’re protecting a valuable investment. A well-maintained mower can last 10-15 years, while a neglected one might need replacing in just 5-7 years.

Your mower worked hard all season. Show it some love before the freeze hits.

The Reality Check: What Do Most People Actually Do?

Full disclosure: Many homeowners do minimal winterization and still get years of reliable service, especially with quality brands like Honda, Toro, or newer Briggs & Stratton engines. Some folks simply park their mower in the garage and it fires right up in spring.

However, this depends on several factors:

Your mower quality - Premium brands tolerate neglect better
Your climate - Milder zones (7-10) are more forgiving
Your fuel type - Ethanol-free gas prevents most problems
Your storage location - Heated garages protect better than outdoor sheds

The bottom line: The steps below represent best practices that maximize longevity and minimize spring frustration. You can certainly skip some steps and probably be fine, but when a $600+ mower dies prematurely or won’t start when you need it, you’ll wish you’d spent the 90 minutes.

What You’ll Need to Winterize Your Lawn Mower

Before you start, gather these supplies:

Cleaning supplies:

Garden hose or pressure washer
Paint scraper or wire brush
WD-40 or silicone spray
Work gloves and safety glasses

Maintenance items:

Fuel stabilizer (for gas mowers)
Fresh engine oil
Replacement air filter (if needed)
Spark plug (if needed)
Wrench set or socket set
Oil drain pan

Storage materials:

Breathable mower cover
Cardboard or drip mat
Optional: wheel chocks

Total time: 1-2 hours Total cost: $20-50 (depending on what you already have)

How to Winterize Your Lawn Mower: 8 Essential Steps

Follow these steps to properly winterize your lawn mower and ensure it’s ready for action next spring.

Step 1: Clean the Mower Deck Thoroughly

Before you winterize your lawn mower, give the cutting deck a serious cleaning. Grass clippings and dirt trapped underneath will hold moisture all winter long. That moisture turns into rust faster than you’d think.

What you’ll need:

Garden hose or pressure washer
Paint scraper or stiff wire brush
WD-40 or silicone lubricant spray
Work gloves

How to do it:

Disconnect the spark plug for safety (or remove the battery for electric models)
Tip the mower on its side (consult your manual for the correct side)
Scrape away caked-on grass and debris with a paint scraper
Spray thoroughly with a hose or pressure washer
Let it dry completely before applying lubricant
Coat the deck with WD-40 or silicone spray to prevent rust

Pro tip: Spray the deck with cooking spray before your last mow of the season. Grass won’t stick as much, making this final cleaning easier.

Step 2: Deal with the Fuel (Gas Mowers)

This critical step to winterize your lawn mower prevents 90% of spring startup problems. Gas sitting in your tank all winter becomes a nightmare. Ethanol fuel attracts water through condensation, creating a corrosive mess that clogs fuel lines and damages engines.

You have two options:

Option A: Add Fuel Stabilizer (Recommended for Detached Storage)

Best for sheds, unheated garages, and outdoor storage.

Fill the tank to about 95% full to minimize air exposure
Add fuel stabilizer according to package directions (typically 1 oz per 2.5 gallons)
Run the engine for 5-10 minutes so stabilized fuel circulates through the carburetor
Turn off and let cool completely

Popular stabilizers: STA-BIL, Sea Foam, or manufacturer-specific products.

Option B: Drain Completely (Required for Attached Garages)

Fire hazards aren’t worth the risk near living spaces.

Run the mower until the tank is nearly empty
Use a siphon pump to remove remaining fuel
Start the engine and let it run until it dies from fuel starvation
Press the primer button a few times to clear the carburetor

Bonus: Use leftover gas to mulch fall leaves—free lawn fertilizer!

Electric Mowers: Battery Care

Remove the battery from the mower
Charge to 40-60% before storage (not fully charged)
Store indoors at room temperature
Check monthly and recharge if needed

Cold temperatures kill battery life faster than you’d expect. Never store batteries in freezing conditions.

Step 3: Sharpen or Replace the Blade

Spring arrives with enthusiasm, and you want your mower ready to match that energy. Dull blades create ragged cuts that stress grass and invite disease. Winter is the perfect time to address this.

Why sharp blades matter:

Clean cuts heal faster and resist disease
Less stress on the engine
Better-looking lawn
Reduced fuel consumption

Your options:

DIY sharpening with a metal file or bench grinder (requires skill)
Professional sharpening at a repair shop ($10-20)
Buy a replacement blade ($15-40) and keep the old one as a spare

How to remove the blade:

Tip the mower (air filter side up)
Use a block of wood to prevent blade rotation
Loosen the center bolt (usually counterclockwise)
Note blade orientation for reinstallation

Pro tip: Buy two blades. Keep one sharp while the other is in use. Swap them mid-season and sharpen during downtime.

Step 4: Change the Oil (Gas Mowers)

Fresh oil before winter storage to winterize your lawn mower prevents internal corrosion and ensures clean lubrication come spring.

Check your manual first. Some modern mowers use synthetic oil that doesn’t require annual changes. Others benefit from fresh oil before long-term storage.

How to change mower oil:

Run the engine for 2-3 minutes to warm the oil (flows easier)
Tip the mower (air filter side up) over a drain pan
Remove the oil fill cap/dipstick and let oil drain completely
Return to upright position and add fresh oil per manual specifications
Check the level with the dipstick—don’t overfill

Typical oil capacity: 15-20 oz for push mowers. Use SAE 30 or 10W-30 (check your manual).

Step 5: Inspect and Replace the Spark Plug

Modern spark plugs last several years, but winter’s an excellent time for inspection. A fouled or worn spark plug causes hard starts and poor performance.

How to check:

Remove the spark plug with a spark plug wrench
Inspect the electrode for wear, carbon buildup, or corrosion
Check the gap with a gap tool (typically 0.030”)
Replace if needed ($3-8) or clean and re-gap if still good

Signs you need a new spark plug:

Black carbon deposits
Cracked porcelain insulator
Worn electrode
Engine misfires or hard starts

Step 6: Clean or Replace the Air Filter

A clogged air filter chokes your engine and wastes fuel. This quick maintenance step takes 5 minutes when you winterize your lawn mower.

Foam filters:

Remove and tap out loose dirt
Wash with warm soapy water
Rinse thoroughly and squeeze dry
Apply a light coat of clean engine oil
Squeeze out excess oil and reinstall

Paper filters:

Remove and inspect
Tap gently to remove loose dirt
Replace if dirty, torn, or oil-soaked ($5-15)
Never wash paper filters

Pro tip: Buy replacement filters in fall when they’re on sale. You’ll have them ready for spring.

Step 7: Lubricate Moving Parts

Keep your mower running smoothly by lubricating key components before winter storage.

What to lubricate:

Wheel axles: Spray with WD-40 or apply light machine oil
Height adjustment mechanisms: Work the lever while spraying lubricant
Throttle cable: Apply a drop of oil where the cable enters the housing
Drive wheels (self-propelled): Check owner’s manual for grease points

Avoid: Getting lubricant on the drive belt—it causes slipping.

Step 8: Choose Proper Storage Location

Where you store your mower matters as much as how you winterize your lawn mower.

Ideal storage conditions:

Dry location: Prevents rust and corrosion
Protected from elements: Shed, garage, or covered area
Stable temperature: Avoid extreme temperature swings
Level surface: Prevents oil and fuel from settling unevenly

Storage tips:

Cover the mower with a breathable cover (not plastic—traps moisture)
Store upright on a level surface
Keep tires inflated to prevent flat spots
Place cardboard underneath to catch any drips
Keep away from water heaters, furnaces, or ignition sources (gas mowers)

No shed or garage? Consider a weather-resistant storage box or tarp with proper ventilation.

Quick Checklist: How to Winterize Your Lawn Mower

Print this checklist and keep it with your mower for easy reference:

The Bare Minimum Approach (If You’re Short on Time)

Based on real homeowner experiences, here’s the absolute minimum to winterize your lawn mower if you’re in a mild climate (Zone 7+) with a quality mower stored in an attached garage:

Option 1: The Sta-Bil Method (5 minutes)

Add fuel stabilizer (Sta-Bil or Sea Foam) to your gas tank
Run the mower for 5-10 minutes to circulate it through the system
Top off with ethanol-free gas if possible
Park it and forget it

Option 2: The Run-It-Dry Method (10 minutes)

Mow until gas tank is nearly empty
Let the engine run until it dies from fuel starvation
Done

What this doesn’t address: Dull blades, dirty oil, clogged air filter. You’ll need to deal with these in spring or mid-season.

Best for: Quality mowers (Honda, Toro, commercial-grade), mild climates, heated storage, people who use ethanol-free gas year-round.

Common Mistakes When You Winterize Your Lawn Mower

Avoid these frequent errors that lead to spring headaches:

❌ Storing with old gas: Ethanol fuel breaks down in 30 days. Always stabilize or drain.

❌ Using plastic tarps: They trap moisture. Use breathable covers or store indoors.

❌ Skipping the deck cleaning: Trapped moisture plus grass clippings equals rust.

❌ Storing battery in the cold: Cold kills lithium-ion batteries. Store at room temperature.

❌ Neglecting the blade: Spring grass growth happens fast. Sharp blades are essential.

❌ Overfilling with oil: Too much oil causes smoking and engine damage.

❌ Forgetting to run stabilized fuel: Stabilizer only works if it reaches the carburetor.

Spring Startup: After You Winterize Your Lawn Mower

When spring arrives, follow these steps for smooth startup:

Reinstall the battery (electric) or reconnect spark plug (gas)
Check tire pressure and inflate if needed
Add fresh gas (if you drained it)
Check oil level with dipstick
Do a test run before the first real mow
Inspect for winter damage or rodent nests

First mow tip: Set the blade high for the first spring cut. Scalping dormant grass invites weeds and disease.

The Bottom Line: Winterize Your Lawn Mower for Long-Term Success

Learning how to winterize your lawn mower isn’t complicated, but it’s crucial for equipment longevity. Spend 1-2 hours now preparing your mower for cold weather, and you’ll save hundreds in repairs or replacement costs.

The payoff:

Reliable spring startup every year
Extended mower lifespan (10-15 years vs. 5-7)
Better performance and fuel efficiency
Healthier lawn from sharp, clean cuts

Your future self will appreciate starting mowing season with a machine that fires up on the first pull instead of making emergency repair shop runs.

Winter prep protects your investment and ensures reliable performance for years ahead. That’s time and money well spent.

Ready to winterize your lawn mower? Tackle these steps on a dry weekend afternoon, and you’ll breeze into spring with confidence.