Replacing the fuel filter on your lawn mower engine is an important part of keeping a periodic maintenance schedule for the whole machine. The fuel filter keeps water and debris from entering the combustion chamber in the engine. If foreign materials enter the combustion chamber the problems that the engine would experience include hard starting or not starting at all, sputtering, uneven idling and lack of power. If the filter is clogged, fuel will not be able to reach the carburetor. Inspect and/or replace the fuel filter every 200 hours, at least, to keep the engine running properly.
Clamp the fuel line exiting the fuel tank between the tank and the fuel filter with a small clip so the fuel will not freely drain from the fuel tank and make a mess. Place another clamp on the fuel line between the carburetor and the fuel filter.
Separate the fuel filter from the fuel line on both ends of the filter. Some fuel filters are hose-clamped into place while others are not. Use a pair of pliers to loosen the hose clamp at both ends of the fuel filter and slide them down the fuel line away from the fuel filter.
Pull the fuel line off of the fuel filter at both ends of the fuel filter. Allow the small amount of residual fuel to drain out of the fuel line and the fuel filter into a gasoline approved container.
Attach the fuel line to both ends of a new fuel filter. Slide the hose clamps into place, if required. Gasoline flows through fuel filters in a specified direction. Be sure to install the fuel filter so gasoline will flow the correct direction.
Remove the clamps from the fuel lines. Start the engine to test the fuel flow through the new fuel filter.