Drain gas tank and crankcase oil. Recycle the oil properly. Add the proper amount and grade of new motor oil. Purchase new fuel. Treat fuel with a fuel stabilizer and fill tank.
Fuel stabilizers help to prevent gumming in the fuel delivery system.
Run the engine for a short time to circulate the additive through the carburetor. Engine with treated fuel can be stored for up to 18 months. Slowly pull starter cord through several times to crank engine and distribute the oil within the cylinder. Replace spark plug. Store the unit with spark plug wire disconnected.