How to Replace the Fuel Filter on an Outboard Engine

by Skip Shelton
Small outboard engine can be fitted with aftermarket inline fuel filters.

Small outboard engine can be fitted with aftermarket inline fuel filters.

Fuel filters on outboard engines perform two primary functions. The first, as the name implies, is to filter out particles in the fuel before the fuel is injected or drawn into the engine for combustion. The second is to act as a water separator. Marine conditions often allow water to enter the fuel storage tanks, and a quality fuel filter limits the volume of water which will enter the engine. Outboard engine fuel filters are primarily available as screw-on or inline types, though some outboards utilize a screen in the engine's fuel pump to restrict particles from entering the engine.

Inline Fuel Filters

1. Remove the engine shroud. Locate the inline fuel filter. Follow the fuel line to locate the inline fuel filter. It will be connected to the incoming line to the engine.

2. Remove the pressure from the fuel system. Disconnecting the fuel connection to the outboard will be sufficient.

3. Remove any clamps connecting the inline filter to the fuel line. Remove the fuel lines from both ends of the filter.

4. Install the new filter by connecting the inline filter to the fuel line. Be sure to check the flow direction of the filter before connecting. Inline filters typically only allow the fuel to move one direction through the filter. Replace any clamps used to secure the inline filter to the fuel line. If no clamps were present, zip-ties may be used to secure the filter in place.

5. Replace the engine shroud.

Screw-on Fuel Filter

1. Locate the fuel filter canister on the outboard. Using a strap wrench or cap wrench, loosen the fuel filter canister by turning counterclockwise. Remove the canister by hand. Be sure not to damage or lose the rubber gasket which secures the filter to the connection point

2. Lubricate the rubber gasket with engine oil, and place the gasket on the new fuel filter.

3. Install the new fuel filter by reversing the process used to remove it.

Fuel Pump Screens

1. Locate the fuel pump. The fuel pump generally has a clear bulb, which will show fuel flowing through it. Some engines have dual carburetors that will each have a fuel pump.

2. Unscrew the fuel bulb to access the mesh screen. While this commonly can be done by hand, any tools required will depend on your engine make and model.

3. Remove the mesh screen from the fuel pump. If necessary, use a fine diameter screwdriver to lift the screen from the connection point. The screens are held in place with pressure and should not be difficult to remove, nor require significant pressure. If the screen is not easily removed, inspect the housing for additional parts that need to be removed to provide access. Do not force the screen, as this may damage it.

4. Clean the screen with brake parts cleaner and a soft-bristled brush.

5. Reinstall the screen. Reinstall the bulb.

Items you will need

  • Replacement fuel filter
  • Zip ties
  • Brake parts cleaner
  • Soft-bristled brush

About the Author

Skip Shelton has been writing since 2001, having authored and co-authored numerous articles for "Disclose Journal." He holds a Bachelor in Science in education and a Master of Business Administration with an emphasis in management from Northwest Nazarene University. Shelton also operates a small automotive maintenance and part-replacement shop.

Photo Credits

  • toy outboard motor image by pearlguy from