Fuel Pump

The two-phase type fuel pump is comprised of the following:

• fuel inlet (from fuel tank)
• inlet check valve
• diaphragm, diaphragm rod and diaphragm spring
• piston and piston spring
• low-pressure inlet (from fuel filter)
• low-pressure inlet check valve
• O-ring, oil seal and fuel seal
• camshaft actuated tappet
• high-pressure outlet check valve
• high-pressure outlet (to cylinder head)
• low-pressure outlet check valve
• low-pressure outlet (to fuel filter)

Fuel is drawn from the fuel tank (9002) by the diaphragm section of the fuel pump (9350). The fuel pump circulates fuel at low pressure (approximately 21-69 kPa [3 to 10 psi]), first through the fuel filter (9155) and then back to the second stage of the fuel pump.

During the second stage, the piston-actuated section of the fuel pump supplies fuel at a pressure of approximately 275 kPa (40 psi) into the cylinder head fuel galleries.

Function and Operation of Fuel Pump

Item	Part Number	Description
1	—	Fuel Inlet (from Fuel Tank) (Part of 9350)
2	—	Inlet Check Valve (Part of 9350)
3	—	Diaphragm (Part of 9350)
4	—	Diaphragm Spring (Part of 9350)
5	—	Diaphragm Rod (Part of 9350)
6	—	Piston Spring (Part of 9350)
7	—	Piston (Part of 9350)
8	—	Low Pressure Inlet (from Fuel Filter) (Part of 9350)
9	—	Inlet Check Valve (Part of 9350)
10	—	O-Ring (Part of 9350)
11	—	Tappet (Part of 9350)
12	—	Camshaft Lobe (Part of 9350)
13	—	Oil Seal (Part of 9350)
14	—	Fuel Seal (Part of 9350)
15	—	Outlet Check Valve (Part of 9350)
16	—	High Pressure Outlet (to Cylinder Heads) (Part of 9350)
17	—	Piston Stage (Part of 9350)
18	—	Spring (Part of 9350)
19	—	Diaphragm Stage (Part of 9350)
20	—	Outlet Check Valve (Part of 9350)
21	—	Low Pressure Outlet (Part of 9350)