Fuel filters are inline filtration components positioned between the fuel tank and the engine’s fuel injectors or carburetor. They mechanically remove particulate contaminants – such as dirt, rust, and scale – from fuel to prevent engine wear and fuel system damage. Filter media typically consists of pleated paper, synthetic fibers, or coalescing materials, rated by micron size to specify particle capture efficiency. Construction varies from in-line canister types to submersible sock filters, with materials chosen for fuel compatibility and pressure resistance. Modern filters may incorporate water separation features to prevent fuel line freezing and corrosion. Replacement is typically based on mileage or time intervals to maintain optimal fuel delivery and engine performance.