Which type of fuel system has the fuel tank located below the carburetor?

In a fuel system where the fuel tank is located below the carburetor, a gravity feed system is utilized. This system relies on the force of gravity to move fuel from the tank into the carburetor. When the tank is positioned at a lower elevation, fuel can flow downwards due to gravitational pull. This type of system is simple and efficient, as it does not require additional components like fuel pumps to move the fuel.

Gravity feed systems are commonly found in smaller engines and outdoor power equipment, where the design allows for a straightforward fuel delivery method. The reliance on gravity means that the fuel will naturally flow into the carburetor as needed, making it a reliable option for applications where supplemental mechanical pumps would be unnecessary or overly complex.

Other fuel systems function differently; for instance, suction feed systems use a pump to create a vacuum that draws fuel into the carburetor, while pressure feed systems actively push fuel to the carburetor under pressure. Diaphragm carburetors incorporate diaphragm mechanisms to assist in controlling fuel flow, but their operation does not specifically require the tank's positioning relative to the carburetor in the manner of a gravity feed system.