Many engine performance problems can be linked to maintenance issues such as stale fuel, dirty air filter, fouled spark plug, and deteriorated oil. A great way to help avoid these problems is to perform an annual tune-up. A clean fuel filter strains the fuel before it reaches the carburetor and prevents foreign particles from clogging your engine. A dirty fuel filter can make the engine run too lean, with diminished performance and uneven operation. The proper filter for your engine depends on the engine's design; therefore, we recommend that you check your engine Illustrated Parts List.