A covered mower stored in a shed in winter

Storing and winterizing a mower

Fuel, stabilizer, E15, and the off-season.

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Why fuel matters

LSU AgCenter says the volatile components of gasoline evaporate over time, and old gasoline will make an engine difficult or impossible to start in spring.

One way: run it dry

LSU says that probably the best way to avoid this problem is to run the engine dry before storage. Ohio State says to drain the fuel tank "in a safe area" and run the engine on idle until it stops before storing equipment for extended periods.

Another way: stabilized fuel

LSU says the alternative is to fill the tank at the end of the season with fresh gasoline that has a stabilizer added. It says the stabilizer must go into fresh gasoline, because it can only stop deterioration, not reverse it.

E15 is not for mowers

EPA says E15, a fuel blend of 15% ethanol and 85% gasoline, cannot be used in engines in nonroad equipment, such as lawnmowers.

Oil and cleaning

LSU says to change the oil before storage and to clean the engine, including its cooling fins. Follow the manual for your mower.

Handling fuel

The CPSC says never to refuel a mower when it is running or while the engine is hot. The AAP says to start and refuel mowers outdoors, not in a garage or shed.

Fuel before storage. Two ways, per LSU AgCenter.

Sources: LSU AgCenter, Preparing Small Engines for Storage; Ohio State University Extension, Power Lawn Mowers; EPA, E15 Fuel Registration; CPSC, Power Lawn Mowers (Publication 5126, PDF); American Academy of Pediatrics, HealthyChildren.org, Lawn Mower Safety: Information for Families.

FAQ

Run it dry, or use stabilizer?

LSU calls running the engine dry probably the best way, and fresh gasoline with stabilizer an alternative approach. Follow the maker's manual for your mower.

What about leftover gas?

LSU suggests using leftover gasoline in another machine or a vehicle rather than keeping it over the winter, and adding stabilizer while it is fresh if you must store it. It warns that gasoline mixed for a 2-stroke engine should not be used in most 4-cycle engines.

General information only. Read the operator's manual before you mow. Keep children and pets indoors or well away from the area you mow, and never let a child ride on a mower as a passenger. The American Academy of Pediatrics says that, in general, children should be at least 12 years old to operate a walk-behind power mower safely and at least 16 to operate a riding mower safely. Before you clear, adjust, or service the blade area, turn the mower off, wait for the blade to stop, and disconnect the spark plug wire; on a battery or corded electric mower, follow the manual to disconnect its power. Refuel outdoors, only with the engine off and cool. Wear sturdy closed-toe shoes and eye and hearing protection. In an emergency, call 911.

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