Proper Engine Winterization Ensures Reliability Come Spring

By Brad Murphy
Vice-President and COO, Subaru Industrial Power Products

When winter comes we bundle up to stay warm, but we aren’t the only ones that need protection against nature’s harsher elements.

There are pieces of equipment that many contractors don’t use much during the winter season, and in some areas of the country, not at all. If equipment will sit idle 30 days or more, it’s necessary to winterize the engine by addressing four primary areas.

Clean and Inspect

  • Give both the machine and its power source a good cleaning.
  • Shut down the engine and allow ample cooling time, then simply wipe the entire unit clean.
  • Use an air compressor to help dislodge any unreachable particles.
  • Clean or change the air filter if necessary.

Fuel Considerations
One of the primary reasons for winterizing an engine is fuel that sits idle for more than 30 days begins to go stale. Stale fuel leads to residue buildup that can plug the small fuel jets in the carburetor, which can cause major headaches and costly repairs. There are two primary methods for addressing this problem:

  1. Drain the fuel and start and run the engine for a few minutes to ensure the fuel lines and carburetor are cleared out. This eliminates any potential issues with stale fuel down the road.
  2. Fill the tank full and add fuel stabilizer. Especially in extremely cold climates, a half-full tank leaves room for condensation buildup. This can cause rusting inside the tank, so it’s important to ensure the tank is completely full. Note that this route is only wise 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
Be sure the engine has fresh oil before storing the equipment. Oil becomes contaminated from normal engine combustion during operation. In addition, if left to sit over the winter, acid may build and 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.

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 storing equipment, as dirty or damaged plugs can cause a decrease in power and lead to poor starting performance come spring.

  • Pull the spark plug and pour a teaspoon of motor oil through the spark plug hole.
  • Pull the recoil 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 or debris to get inside. It also provides the dual benefits of distributing the oil across the head, rings and valves, and preventing moisture and rust in the combustion chamber.
  • Replace the spark plug and be sure to set the gap as instructed in the owner’s manual.

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