Outdoor

How to winterize a lawn mower (gas and battery)

By Roof & Router Team. Updated October 11, 2026.

When should you winterize a lawn mower?

Do it right after your last mow of the season, before the mower sits unused for a month or more. Untreated gas is the main reason. Briggs & Stratton says gasoline goes stale in about 30 days after pumping. Cub Cadet warns that old gas can turn to a thick, molasses-like gum.

Should you drain the gas or add stabilizer?

The big engine makers disagree, so follow the manual for your engine.

Honda says running the carburetor dry takes under 3 minutes.

Either way, add stabilizer to fresh gas; Honda notes it will not restore stale fuel. Run the engine only outdoors because of carbon monoxide.

What ethanol gas is safe for a lawn mower?

Regular E10 gas, with up to 10% ethanol, is fine for most mowers. Honda says not to use gas with more than 10% ethanol. Higher blends attract water and can corrode fuel parts.

Do not use E15. The EPA says E15 is not for use in lawn mowers and other small engines. It is often sold at the same pump as E10, so check the label.

How do you winterize a gas push mower, step by step?

1. Handle the fuel. Use one of the two methods above.

2. Change the oil. Briggs & Stratton says to warm the engine slightly so the oil thins and drains faster. Drain it and refill with the type and amount in your manual.

3. Disconnect the spark plug wire. Do this before you tip the mower or touch the blade. The Home Depot’s blade guide calls for it to prevent an accidental start.

4. Clean or replace the air filter. Briggs & Stratton says to inspect it and clean or replace it if dirty.

5. Check the spark plug. Cub Cadet suggests replacing it if it looks worn or damaged.

6. Tip the mower the right way. To reach the underside, tilt the mower so the air filter and carburetor face up. Cub Cadet and The Home Depot both say this. Tipping it the other way risks oil or fuel running into the air filter. The Home Depot also suggests draining the tank before tipping to avoid spills. Do it outdoors, away from flames and sparks, into an approved gas can. Your manual has the final say on direction.

7. Clean the underside of the deck. Scrape out packed grass, dirt and debris. Wet clippings hold moisture against the steel through the winter.

8. Sharpen or replace the blade. Wear thick gloves. Sharpen with a file or sharpening tool, or replace a badly worn blade. After sharpening, balance the blade on a center point. If one side drops, file a little more off the heavy side and test again. Cub Cadet suggests a coat of chassis grease on the blade to prevent rust.

9. Clean the engine. Brush or blow grass and debris off the engine and cooling fins.

Where should you store a gas mower for winter?

Store it in a cool, dry shed or garage. Cover it to keep dust off.

Keep it away from any appliance with a pilot light or flame, such as a furnace or gas water heater. Cub Cadet gives this warning. Gas vapor from the tank or carburetor can reach a flame and ignite. This matters most with the Briggs & Stratton method, since the tank stays full. Store gas cans away from those appliances too.

For other cold-season jobs around the house, see the winterize house checklist.

How do you winterize a riding mower battery?

Follow the same fuel, oil, filter and deck steps as a push mower. The battery needs extra care.

Briggs & Stratton says to remove the battery for winter:

1. Disconnect the negative (-) cable first, then the positive (+).
2. Clean the terminals with a terminal cleaner.
3. Apply a protective coating to the terminals.
4. Store it in a cool, dry place, away from gas cans, water heaters and furnaces.

Many owners also keep the battery on a maintainer over the winter. If you do, use one made for your battery’s type and voltage, and check the mower or battery manual first.

How do you store a battery-powered mower for winter?

Battery makers advise against storing packs in extreme heat or cold, or fully charged. Here is what the guidance says:

Brands differ, so check the battery manual for its exact temperature range. A spare room shelf or a closet works. An unheated shed or a hot attic does not.

For the mower body, clean grass off the deck and wheels and sharpen the blade. Remove the battery and safety key before cleaning under the deck or touching the blade. Keep water away from the motor and battery port.

What should you do in spring before the first mow?

Quick answers

Should I drain the gas from my lawn mower for winter? It depends on the engine maker. Honda says stabilize the tank and run the carburetor dry, or drain the fuel system for storage over 90 days. Briggs & Stratton says fill it with stabilized fuel and run it a few minutes (Briggs’s tractor storage guide says about 10).

Is E15 safe for lawn mowers? No. The EPA says E15 is not for use in lawn mowers and other small engines. Use E10 or ethanol-free gas.

Which way do you tip a lawn mower? Tip it so the air filter and carburetor face up. This keeps oil and fuel out of the air filter.