With the arrival of fall most of the lawn and garden work is behind us for the year. Soon the lawn mowers, leaf blowers, string trimmers, and tillers will no longer be needed until next spring. So what do you plan to do with this small engine-powered equipment until you need it until then? Are you just going to throw a plastic cover or old bucket over the engine and let it ride out the winter where it sits? If you are not concerned about getting the longest service out of your equipment or don’t mind possibly having to take the carburetor apart in the spring to unstop the jets, then don’t worry with winterizing. However, if you do want to get the longest life and best service out of your small-engine powered equipment, there are several steps that you can take at the end of the season.

First, change the oil. As a four cycle gasoline powered engine runs, the oil not only lubricates the moving parts, but it also cleans the internal surface of the engine cylinder and pistons. The oil collects acid, water, metal particles, and other foreign materials that form sludge in the engine. If oil with the contaminants is allowed to stay in the engine over the winter, deterioration of internal engine parts and seals can occur. Replace the old oil with fresh oil of the proper viscosity. Your owner’s manual will indicate the proper oil, usually it be will SAE 30 or 10W30. Two cycle engines on chain saws and string trimmers do not have an oil sump to drain because the oil is mixed directly into the gasoline.

Next check the air filter. The end of the season is a good time to change or clean the air filter especially if it has not been done during the season of use. About 10,000 gallons of air are consumed in the combustion process for every gallon of fuel used by the engine. The air filter cleans abrasive dust and dirt out of the air prior to entering the engine. A dirty air filter can restrict the air flow and cause the engine to run rich. Foam filters need to be re-oiled after cleaning. Use the same type of oil as was used in the crankcase. Also, check the spark plug to assure it is not fouled and that it is properly gapped.

Fuel is another area of concern for both four and two-cycle engines. There are two approaches to winterizing your small engine when dealing with the gasoline left in your fuel tank at the end of the season. One approach is to drain the fuel out of the gas tank and then start and run the engine to get all the fuel out of the fuel lines and carburetor. If fuel sits for a long time it ages and residues can form that may plug the small fuel jets in the carburetor. Removing the gasoline eliminates this problem. After running the engine out of gas and letting it cool, take the spark plug out of the cylinder and squirt or pour about a tablespoon of oil into the cylinder. With the spark plug wire off, slowly pull the starter cord or use the starter to turn the engine over a couple of times to distribute the oil over the internal surfaces of the cylinder and piston.

The other option in dealing with fuel is to put a gas stabilizer into the gas tank. A gas stabilizer will keep the gas "fresh" for up to two years if it is added to the gas right after it is purchased or for one year for a two cycle gas/oil mixture. With a freshener in the fuel, it is not necessary to drain the tank or get the fuel out of the carburetor. It is, however, necessary to run the engine a couple of minutes to be sure that the "freshened gas" gets into the carburetor. This procedure is simpler and is especially good if you have a metal gas tank. A full metal gas tank will keep moisture out of the tank and prevent rust from forming on the inside of the gas tank. The rust particles act as abrasives inside the engine.

This is also a good time to sharpen the blade and lubricate wheel bearings and throttle cables. Use lubricants such as WD-40 or silicone - using oil will cause dust and foreign material to stick to the oil and possibly damage bearings. Cleaning the outside of the engine and deck area are also important. If oil and grass have accumulated on the engine the cooling efficiency especially for an air-cooled engine is reduced. Most small engines are air-cooled. Caked grass can trap moisture and cause rusting of metal mower decks and lead to reduced service life. Finally, store your small engines inside if possible, but if you must store them outside, cover them loosely with a waterproof cover so that air can circulate underneath. Be sure to properly anchor the cover.