8C. Diaphragm Type Carburetor (Option); 8C-1 Operation And Construction - Robin EH09D Service Manual

8c. DIAPHRAGM TYPE CARBURETOR (OPTION)

8c-1 OPERATION AND CONSTRUCTION

1. ENGINE IMPULSE
The alternating action of the positive pressure and negative pressure inside the engine crankcase oper-
ates the fuel pump diaphragm.
2. FUEL PUMP DIAPHRAGM
The fuel pump diaphragm undulates in response to the engine impulse and as a result of that movement
it feeds the fuel through the fuel pump valve.
3. FUEL INLET
The fuel inlet is the opening through which fuel is sucked from the fuel tank.
4. INLET VALVE
The inlet valve opens when the diaphragm is submitted to the action of a negative pressure in response
to the movement of the pump diaphragm and the inlet valve shuts when it is submitted to a positive
pressure.
5. OUTLET VALVE
Oppositely to the inlet valve, the outlet valve shuts when it is submitted to the action of a negative
pressure and opens when submitted to a positive pressure.
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Fig. 8-7
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