Section II. FUEL SYSTEM

Section II. FUEL SYSTEM

5-9. General

(2) Tag and disconnect electrical lead and

remove glow plug from precombustion chamber.

The fuel system consists of a supply tank, fuel

injection valves, fuel injection pump, pressure gage,

(3) Remove the nut securing the nozzle and

body in the precombustion chamber.

fuel filters, transfer pump, vent valve and primer

pump. The transfer pump draws fuel from the fuel

(4) Lift out the nozzle (5, fig. 5-17) and body

tank and delivers the fuel through the primary and

(1) and discard the two seals (2 and 4).

secondary fuel filters to the fuel injection pump.

(5) Unscrew the nozzle (5) from the body (1).

The injection pump delivers the fuel under high

b. Cleaning. Clean the fuel discharge hole in the

nozzle. Remove any carbon deposits.

pressure to the injection valves, where it is sprayed

c. Repair. Inspect the nozzle for an ac-

into the engine precombustion chambers. The

accessory drive shaft drives the governor, fuel

cumulation of carbon, eroded orifice and plugged

injection pump camshaft, service meter and fuel

screen. Replace the nozzle if necessary.

transfer pump.

d. Testing. Test fuel injector for proper

operation by mounting injector in test fixture

5-10. Fuel Injectors and Glow Plugs

examining the spray pattern, and checking the

a. Removal and Disassembly.

injector unseating pressure. Unseating pressure

(1) Disconnect the fuel line (fig. 5-16) at the

must be between 400 and 800 psi. If pressure fails

fuel injectors. Cap or plug openings.

to reach 400 psi, replace the injector. Test for

leakage by applying 300 psi pressure. If pressure

falls more than 100 psi in 30 seconds replace the

injector. Replace an injector that does not produce

an even atomized spray pattern after the orifice has

been cleaned. If screen filter in the injector is

broken or clogged, replace the injector nozzle.

NOTE

Only the capsule type nozzle and injector body need be

replaced. Tighten nozzle in valve body only finger

tight.

e. Reassembly and Installation.

(1) Install the nozzle (5, fig. 5-17) to the body

(1) and tighten finger-tight. Insert the injector into

the opening in the precombustion chamber (fig. 5-

16).

(2) Install new seals (2 and 4, fig. 5-17).

(3) Secure with the nut (3) and tighten to a

torque of 100 to 110 foot-pounds.

Figure 5-16. Fuel injector, removal and installation.

5-20