CHAPTER 4 MAINTENANCE OF FUEL SYSTEM

TM5-6115-585-34 NAVFAC P-8-623-34 TO-35C2-3-455-2 TM-05684C/05685B-34 CHAPTER 4 MAINTENANCE OF FUEL SYSTEM Section I. DESCRIPTION AND FUNCTION 4-1. GENERAL. The engine fuel system consists of two pressure system; the low pressure system and the high pressure system. In the low pressure system, a fuel pump may draw fuel from an external source to till set tank or set tank may be filled manually. If an external fuel source is selected, a float valve assembly in the set tank maintains the fuel level in the tank. Two other fuel pumps (in series) draw fuel from the set tank and force the fuel through a primary strainer, two secondary filters, and a check valve assembly, to the injection pump. In the high pressure system, the fuel injection pump forces the fuel, under high pressure, to the fuel injection nozzles. The injec- tion nozzles provide fuel to each combustion chamber of the engine. A small quantity of unused fuel is returned from the injectors and injector pump to the fuel tank. A cam and gear on the camshaft drives the fuel injection pump. The gear drives the pump face gear, providing fuel distribution to each cylinder in the proper order. The cam operates the pump plunger, pressurizing fuel to the nozzles. A control sleeve meters fuel by controlling the length of time the plunger spill port is closed, maintaining pressure, and there- fore, the amount of fuel delivered in each stroke. The pintle type injection nozzles are conventional inward opening with adjustable opening pressure. They are factory adjusted to open at 1900 to 1950 psi. Section II. MAINTENANCE OF FUEL TANK 4-2. FUEL TANK. a. Inspect. On ASK equipped generators, refer to Operator and Organizational Maintenance Manual and remove left panel and side closure assemblies. Inspect the fuel tank per Operator and Organizational Maintenance Manual. b. Remove. Remove fuel tank and remove compo- nents per Operator and Organizational Maintenance Man- ual. c. Test. Plug all but one opening in the fuel tank. Con- nect a regulated low pressure air supply to tank opening. Apply 3/4 to 1-1/4 psi to tank and submerge tank into water. Check for leaks. d. Repair. WARNINGS Observe all safety precautions when soldering fuel tank. Avoid breathing fumes generated by lead soldering. Eye protection is required. Hot refueling of generators while they are oper- ating poses a safety hazard and should not be attempted. Hot engine surfaces and sparks pro- duced from the engine and generator circuitry are possible sources of ignition. Severe injury, death and/or damage to the equipment may result. (1) Repair leaks in fuel tank by soldering, (2) Clean repaired area with dry cleaning solvent Federal Specification P-D- 680. (3) Paint as required with MIL-T-704, type A, semigloss, olive drab, color no. 24087. e. Install. (1) On ASK equipped generators, refer to Opera- tor and Organizational Maintenance Manual and install left panel and side closure assemblies. Install the fuel tank and components per Operator and Organizational Maintenance Manual. (2) Fill tank with fuel oil. Change 7 4-1/(4-2 blank)