How to Winterize a Lawn Mower and Equipment

The first order of business is to address the fuel. Over several months, fuel begins to break down and turn to varnish, leaving nasty deposits. This is especially problematic with small engine carburetors as the fuel bowl hangs upside down on most. This means that this old fuel and deposits have a tendency to settle in the bowl right where the fuel pick-up brings fuel into the carb body. If the fuel has settled and formed deposits / clogged, it will do a very-common “fire up and die right away” symptom when you go to start the carb in the summer. To prevent this, fill the fuel tank up with fresh gas, and add the recommended amount of Sta-bil fuel stabilizer to the fuel. Now, start the equipment and let it run for 2-3 minutes. You want to be sure that the fuel that contains Sta-bil is completely circulated into the carb. It is always better to store equipment with a complete tank of gas unless you plan on completely draining the fuel tank AND the carburetor, which is usually a bit more work. Just draining the gas tank by itself will not address the fuel that’s still in the carb, and this fuel is what can break down and clog the carb. Now, the engine has run for several minutes and allowed the oil to heat up. Next step is to change the oil.

When putting equipment away for the winter, a fresh oil change insures your equipment is ready to go for next season. Change your oil with the proper oil and filter if applicable. Most small engines don’t have an oil filter, but some do. At the same time, remove the old air filter. Some small equipment doesn’t have an air filter, but most do. Don’t replace the filter yet – the next step is to fog the engine!

When any engine or equipment is stored for a long period of time, corrosion on bare metal parts that have exposure to the air can be a major concern. This is especially true in northern climates were winter “wet” conditions can cause massive humidity issues where your storage shed or garage is rapidly changing temperatures. You’ve seen this phenomenon before – go outside to the shed on a “warmer” spring day after it has been below freezing for some time and the snow is melting – you’ll notice everything in the shed is covered in wet moisture from the rapid temperature changes. Put that environment inside an engine, and over time corrosion can create issues. Fogging oil ensures this won’t happen. Fogging oil is a thin, coating oil in a spray can. It’s meant to be ingested into the intake or carb while the engine is running. Some of the oil burns off, but the majority of it coats the cylinder walls and valves, putting a layer of protection on them. To use fogging oil, after step 2 – you already have your air filter removed from your equipment – or – if you don’t have an air filter on your equipment, locate the air intake. Start the engine again. Now, spray your fogging oil into the intake in short, 1 to 1.5 second bursts. You will notice that the engine stumbles badly when you spray the fogging oil, and can even die. Try to keep it running for about 10 seconds, then spray a final big spray in the lawnmower and either shut it off or allow the fogging oil to stall the engine. Then, install your new air filter. In the spring when you fire the engine up, the fogging oil will burn off, and sometimes the engine will run a rad rough until all the oil is expelled.

The final step of winterization is one you can do now, or wait until spring start up, and that is installing a new spark plug. Spark plugs in 2-stroke engines (any engine where you mix gas/oil) live a pretty rough life and its recommended that every season they are changed. Small 4-stroke engines can sometimes get by for multiple years on one plug, but at less than $5.00 a plug, it’s a good practice to simply change it. At this point, your winterization is complete!