The air filter needs to be clean and in good condition in order to stop dirt, dust, and debris from getting into the engine. It is recommended to clean the air filter after every 4 hours of use and should be changed every 100 hours or every 3 months, whichever comes first.
Fuel filters can be removed and cleaned of residue, however if there is debris clogging the mesh screen inside the filter it should be replaced. Some fuel filters are located in the fuel line and others are located inside the fuel tank.
Before storing the string trimmer, spray a degreaser on greasy and dirty areas, let it sit for 10-15 minutes then wipe the sprayed area with a clean cloth. Rinse off the string trimmer with a hose and dry completely.
String trimmers require clean, fresh fuel for best performance. During the off season when your string trimmer is being stored, the fuel should either be drained or a fuel stabilizer should be added to prevent clogs in the carburetor.
Spark arrestors are inside the muffler of the string trimmer engine. They should be cleaned or replaced every 25 hours of use or once a season. Spark arrestors made of a fiberglass material should be discarded because they are not made to be cleaned and reused.