If the lawnmower has no shut off valve on , consider installing one, otherwise drain the tank and run the engine until it uses all the before storing. At of the lawn mower season if your lawmnower has a shut-off valve on , turn off the valve and run the engine until it quits. This assure all the is used up in the carburetor before storing. Also use a shut off valve as a safety feature during the season when storing equipment in a garage or storage building between mowings. It helps with leaks due to a bad needle valve or leaking carburetor., Weight: 0.32187490252 Pounds, Manufacturer: Kueohse