Engine Hibernation

For many contractors, equipment is often used very little during the winter season – and in some areas of the country, not at all. If a piece of equipment will sit idle 30 days or more, it’s necessary to winterize the engine. Winter has arrived for many of us already, so addressing the following areas right away will help ensure equipment is ready to go in the spring.

Fuel Considerations

One of the primary reasons engines must be winterized if idle for more than 30 days is because that’s the point when fuel begins to go stale, making fuel the next item to address for proper winterization. Stale fuel leads to residual build-up, which can plug the small fuel jets in the carburetor and cause major headaches and costly repairs. There are two primary methods to address this problem.

The best approach is to drain all of the fuel out of the gas tank, then start the engine and run for a few minutes to ensure the fuel lines and carburetor are free. This option eliminates any potential issues with stale fuel down the road.

Another acceptable approach is to fill the tank full, then add fuel stabilizer. Especially in extremely cold climates, a half-full tank leaves room for condensation buildup. This can quickly cause rust to form inside the tank, so it’s important to ensure the tank is completely full. However, it’s only wise to go this route if the engine has a fuel shut-off valve. Upon filling the tank, shut off the valve and run the engine until it dies. This ensures the carburetor is dry and leaves no chance for moisture accumulation.

Oil Adjustment

In day-to-day operations, changing the oil is considered a routine part of a maintenance program. When it comes to winterization, the same rules apply. Oil becomes contaminated from normal engine combustion during operation. Acid builds and if left to sit over the winter, may cause corrosion. The same is true of water and other particles that can contaminate oil during typical operation. Also, oil that sits for too long can become thick and gummy, preventing a smooth start come spring. Be sure the engine has fresh oil before storing the equipment. Because colder temperatures may still be present when it’s time to start up the equipment in the spring, it’s also a good idea to adjust viscosity at this time. Multi-viscosity oil is a great option, especially in areas with unpredictable or harsh temperatures. It recognizes outdoor temperature and adjusts to proper viscosity.

Spark Plug Check

Finally, it’s important to replace spark plugs prior to winterization when it comes to gas engines, as dirty or damaged ones can cause a decrease in power and lead to poor starting performance in the spring. Remove the existing spark plugs, then put a teaspoon of oil into the plug. Pull the recoil over a few times until resistance reaches its maximum. It’s at this point, top dead center, that both the intake and exhaust valves are closed, leaving no room for moisture, debris — or even a pest — to get inside. It also provides the dual benefit of distributing the oil across the head, rings and valves, and preventing moisture and rust in the combustion chamber. Upon replacing with a new spark plug, set the gap as instructed in the owner’s manual and replace.

Spending just a few minutes to winterize an engine may save a lot of time and frustration in the future by better ensuring dependable operation come spring.

Brad Murphy is vice president and COO of Subaru Industrial Power Products, based in Lake Zurich, Ill.