Chainsaw Power Unit Maintenance – Air Filter Maintenance

Chainsaw Maintenance and Cross-Cutting – City & Guilds Unit 201/ 202


Chainsaw Power Unit Maintenance – Air Filter Maintenance

Air filters are often the first part of the power unit practical assessment to be discussed and maintained in the City & Guilds NPTC Unit 201. You will be asked to explain the function and maintenance requirements. Once that is complete, you would then demonstrate that on your own chainsaw.

Your assessor may work on one aspect at a time or allow time for you to lay all the relevant components out ‘Blue Peter’ style. This may be beneficial for confident students.

The air filter prevents airborne debris from entering the carburetor and combustion chamber, which would otherwise cause rapid wear to the cylinder and piston.

Also, air-flow is regulated. This contributes to maintaining a favourable air to fuel ratio for efficient combustion, lower emissions and optimum engine performance & lifespan.

Generally, they are located to the rear of the saw and can often be accessed by removing a panel or the whole top engine cover or guard (Husqvarna 550/560XP, Stihl 261). An initial visual assessment is possible before removing for more thorough cleaning and inspection. Take time to brush any significant debris away before removing. You can use gravity to steer debris away when removing by holding the saw upside down on vertical entry saws.

A sponge or paper tissue can also be used as well as a choke to prevent debris from entering, as maintenance continues on the rest of the machine.

  • Remove top cover/guards or shields
  • Initial clean
  • Turn saw to prevent debris from entering the carburetor
  • Brush debris away
  • Apply choke/cloth to carburettor entrance

Cleaning can now be carried out but remember that not all air filters are the same. Some paper or fabric types may require a new replacement whereas most professional saws will have a washable plastic film filter. These professional chainsaws will often have split-able plastic film filters; air stream can be used to dislodge debris from the inside – out. Check for holes or tears in these types of filters; a clue will be accumulated debris inside the filter.

Main air filter types

Paper/fabric – brush/airline only – replace with new when contamination severe

Plastic/film – wash in warm soapy water. Dry film thoroughly

Inspect for damage

  • holes/ tears
  • contamination
  • broken parts

Remember the links to other components here with the carb settings and the fuel mix contributing to efficient combustion. The neglected air filter may give rise to a range of poor performance symptoms.

  • blocked – smoke – poor performance
  • torn – too much air higher revs?


However, many saws have electronic controls so you may not notice any of the above as the saw adjusts to cope…