Fuel System Operation and Tests
FUEL SUPPLY PUMP OPERATION--ROTARY
The Sofabex fuel supply pump used with Lucas and
Stanadyne rotary fuel injection pumps uses an eccentric
lobe on the engine camshaft to operate lever (G) on
supply pump to pressurize fuel system.
Fuel flows from the fuel tank at gravity pressure to the
inlet side (D) of the diaphragm-type pump.
As lever (G) rides on the high side of the camshaft lobe,
rod (F) pulls diaphragm (I) down. Suction pressure opens
the inlet check valve (C) and fuel is drawn into the pump.
As the camshaft lobe rotates to the low side, return spring
(E) forces diaphragm (I) upward. The resulting fuel
pressure closes inlet check valve (C) and opens oultlet
check valve (B), delivering fuel through outlet (A) to the
Hand primer lever (H) is provided for manually forcing fuel
through the system to bleed air from the fuel filter, lines,
B--Outlet Check Valve
C--Inlet Check Valve
H--Hand Primer Lever