Fuel must be kept clean, or the jets in the carburetor could be blocked, or corrosion can occur. So fuel systems always contain filters.
In a carbureted system, a fine filter of nylon or gauze is fitted to the pick-up pipe in this gasoline tank. A large surface area is provided to allow adequate flow rate, and better filtering.
An in-line filter, which is usually made of a clear or opaque plastic, is normally fitted either between the tank and the pump, or between the pump and carburetor.
This filter traps dirt, and water. The amount of contamination can usually be seen through the plastic.
