Fuel filter filters dirt out of fuel before reaching the engine. Dirt in this case can include water, mud or even air. Without a fully functional fuel filter and regular maintenance a decrease in motor output can occur, or damage due to erosion and corrosion.

Various types of fuel filter can be used:

• Cartridge
• Spin-on, which is a cartridge provided with a thread. (Consists of a sheet metal case and a catridge. In some cases a riser pipe is integrated.)
• Pipe-filter or in-line filter