Honda EB4000 Owner's Manual page 24

Fuel filter service
The filter prevents dirt or water which may be in the fuel tank from entering
the carburetor. If the engine has not been run for a long time, the filter should
be cleaned.
1. Turn the fuel valve OFF. Remove the filter cup.
2. Clean the cup thoroughly.
3. Reassemble. Do not damage the rubber gasket.
m After installing the filter cup, check for fuel leaks and make sure
the area is dry before starting the engine.
FUEL VALVE