Helping Your Chainsaw Breathe Easier

This saw is ready to have its air filter cleaned using compressed air and carburetor cleaner as a solvent. Photos by Brett R. McLeod.

Your beloved chainsaw engine is essentially a fiery air pump. The process starts by drawing in fresh air, compressing that air, and then adding a dose of fuel and a spark – resulting in combustion. If you have a rough-running or underpowered saw, before investigating more complicated causes, consider whether a dirty air filter is restricting airflow.

While many manufacturers recommend replacing the air filter annually, checking and cleaning the air filter should be a daily maintenance item, akin to sharpening and tensioning your saw chain. How you clean your air filter will depend on its condition, and whether you’re in the woods or at home, as well as the type of air filter your saw uses.

While you won’t be able to get your air filter as clean in the woods as when you have access to equipment in a home workshop, on-the-go cleaning is a necessary field skill. Start by removing the air filter cover. On some saws, there’s a simple knob that loosens by hand; on others you’ll need a screwdriver or scrench. Remove the cover and wipe out the airbox. Some air filters have a “pre-filter” that is essentially a foam or felt band that wraps around the air filter. In this case, brushing the pre-filter or blowing on it from the inside out is usually enough to improve the situation.

Removing the air filter will allow you to shake, tap, and blow debris off the filter material. Do this gently to avoid driving debris deeper into the filter. It’s important to remember that removing the air filter also exposes the carburetor and engine to contamination. Blow or sweep all debris from around the intake manifold and carefully remove the filter. A small paintbrush is ideal for sweeping away the loose debris on and around the air filter. Plug the open manifold with a clean rag to prevent contamination.

This filter separates into two pieces so you can clean it from the inside out. It’s important to use compressed air to push out dirt and debris; if you use high-pressure air on the outside, you’ll just drive the dirt deeper into the filter.

If you’re in your workshop or have access to compressed air, you’ll be able to clean the filter much more thoroughly. Using an air nozzle, blow from the inside of the filter out, using a back-and-forth motion. Many saws also use a felt or nylon mesh two-piece air filter that can be separated to facilitate cleaning from the inside (see second photo). After your initial pass with compressed air, spray the outside of the filter with carburetor cleaner and then use the air nozzle to blow it out once again from the inside. This second pass with the assistance of the carburetor cleaner will leave all but the worst of air filters looking like new.

Inevitably, over time, tiny particulates will clog the filter, necessitating not just a cleaning, but outright replacement. Periodic replacement, combined with regular cleaning, will result in a better running saw with less wear to internal components. And, if that’s not enough incentive, a clean air filter will also have the added benefit of reducing fuel consumption.

To illustrate the benefits of using both compressed air and carburetor cleaner as solvent, note that this filter is visibly cleaner. For comparison purposes, the far-right square was not cleaned.