Service lawn mower

Properly store your lawn mower for winter with fuel treatment, oil change, blade care, and spark plug maintenance to ensure easy starting next spring.

Why it matters#

The number one cause of spring lawn mower problems is old fuel left in the system over winter—it gums up the carburetor and turns a simple pull-start into a frustrating repair job. Twenty minutes of fall prep saves you from carburetor cleaning that costs $75-150 at a repair shop or a lot of headache doing it yourself.

What you'll need#

Tools#

• Socket wrench with spark plug socket (usually 13/16")
• Screwdriver
• Oil drain pan
• Funnel

Materials#

• Fuel stabilizer OR empty container for draining fuel
• Fresh engine oil
• Replacement spark plug (optional)

Safety gear#

• Heavy work gloves
• Safety glasses

Steps#

1. Deal with the fuel (choose one method)#

Option A - Stabilizer: Add fuel stabilizer to FRESH gas (not old fuel), fill the tank, and run the engine for 10 minutes to circulate it through the carburetor. Option B - Drain: Run the mower until it stalls and won't restart, or siphon out remaining fuel. Either method works—the goal is preventing stale fuel from gumming up the carburetor.

2. Disconnect the spark plug wire#

Pull the wire boot off the spark plug before any blade or maintenance work. This prevents accidental starting—even a small bump to the blade can cause the engine to turn over.

3. Change the oil#

Run the engine briefly to warm the oil (it drains better warm). Place a drain pan under the mower and tip it with the carburetor side UP to prevent fuel leaking into the air filter. Drain oil completely, then refill with the type specified in your owner's manual.

4. Clean or sharpen the blade#

With spark plug disconnected, tip the mower and remove the blade (turn the bolt counterclockwise). Sharpen with a file if dull—maintain the existing angle and check balance afterward. Or simply swap in a fresh blade and sharpen the old one at your leisure.

5. Service the spark plug#

Remove the plug with a spark plug socket. If the tip is light tan, it's healthy. If it's black, oily, or damaged, replace it. Gap the new plug according to your manual and apply a few drops of oil into the spark plug hole before installing.

6. Clean or replace the air filter#

Foam filters can be washed with soapy water, dried completely, and lightly oiled. Paper filters should be brushed clean or replaced if dirty. A clean filter protects your engine.

7. Clean the deck and store properly#

Scrape grass buildup from under the deck. Store the mower in a dry location, covered with a breathable material (not plastic sheeting, which traps moisture).

Pro tips#

• Never add stabilizer to old fuel—it won't revive gas that's already gone bad; stabilizer only preserves fresh fuel
• Keep a spare sharpened blade on hand for quick mid-season swaps
• Late winter is actually the ideal time to drop your mower at a repair shop—parts are plentiful and shops aren't busy

Warnings#

• Always tip mowers with the carburetor/air filter side UP—tipping the wrong way floods the air filter with oil and fuel
• Handle blades with heavy gloves—even dull blades can cut you

When to call a pro#

Take your mower to a small engine repair shop if the carburetor is already gummed up and the mower won't start, if the blade is badly damaged or bent (never run a bent blade), or if you're uncomfortable working with fuel and spark plugs. A full professional tune-up typically costs $50-100 and includes everything above.