Before changing/cleaning the air filter, first determine whether your machine has a paper or foam air filter. Paper air filters are replaced; while the foam ones are cleaned.
Steps for Changing a Paper Air Filter
Unscrew the cover and remove the paper air filter.Insert a new paper air filter with the pleat facing out. Screw the cover back on.
Steps for Cleaning a Foam Air Filter
Unscrew the cover. Remove air filter unit and discard the old foam. Clean the air filter unit.
Soak the new piece of foam in clean engine oil.
Squeeze out the excess oil using a clean rag. Insert new foam in air filter. Ensure the lip protrudes over edge of the unit. Screw the cover back on.