How to Winterize Your Lawn Mower

Winterization is the difference between a mower that fires up on the first pull in April and one that sits dead in the garage while you pay a repair shop to flush a gummed-up carburetor. Modern ethanol-blended gasoline begins to degrade in as little as 30 days, leaving behind varnish that clogs small passages and ruins fuel injectors or carburetor jets. By spending an hour in the fall to stabilize or empty the fuel and prep the engine, you are effectively buying yourself insurance against a costly breakdown when the grass starts growing again. Done well, this process is systematic and focused on preservation. You are removing corrosive elements like old oil and acidic grass clippings while ensuring the machine is stored in a way that prevents internal rust. Treat this as a ritual of respect for your equipment, and it will reward you with years of reliable service without the headache of mid-season mechanical failures.

1. Stop fuel degradation now. Run the engine until it stops from lack of fuel, or add a fuel stabilizer to a full tank and run the engine for five minutes to ensure the treated fuel reaches the carburetor. If your mower has a fuel shut-off valve, close it before turning the machine off.
2. Flush corrosive residue. Warm the engine slightly to help the oil flow, then disconnect the spark plug wire for safety. Place a drain pan under the oil plug, remove the bolt, and drain the old, acidic oil completely before replacing the plug and adding fresh, manufacturer-recommended oil.
3. Guarantee spring ignition. Remove the spark plug using a socket wrench and inspect the tip for heavy carbon buildup or electrode erosion. If it looks worn or fouled, replace it with the exact part number specified in your owner's manual.
4. Remove decay-causing buildup. Tip the mower on its side with the air filter and carburetor facing upward to prevent oil from leaking into the filter. Scrape away all dried grass clippings and debris from the underside of the deck using a stiff putty knife.
5. Balance the blade perfectly. While the mower is tilted, check the blade for nicks or rounding. Remove the blade using a block of wood to hold it steady, sharpen the edge with a metal file or bench grinder, and ensure it is balanced before reinstalling.
6. Seal metal against winter. Wipe down the mower chassis with a damp cloth to remove acidic grass residue that can corrode the deck over time. Lightly spray metal linkages and the undercarriage with a silicone-based lubricant to prevent rust during the damp winter months.