4-2 FUEL AND LUBRICATION SYSTEM
FUEL VALVE
When the engine has started, negative pressure (vacuum) is generated at the intake port. The negative
pressure causes the fuel valve diaphragm to compress its spring, opening the fuel passageway and allow-
ing the fuel to flow to the carburetor.
When the engine has stopped, the spring pushes against the valve, closing the fuel passageway, and stop-
ping the flow of fuel to the carburetor.
To carburetor
Negative pressure
Air vent hose
From fuel tank
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