TM5-6115-585-34NAVFAC P-8-623-34TO-35C2-3-455-2TM-05684C/05685B-34CHAPTER 4MAINTENANCE OF FUEL SYSTEMSection I. DESCRIPTION AND FUNCTION4-1. GENERAL.The engine fuel system consists of two pressure system; thelow pressure system and the high pressure system. In the lowpressure system, a fuel pump may draw fuel from an externalsource to till set tank or set tank may be filled manually. If anexternal fuel source is selected, a float valve assembly in theset tank maintains the fuel level in the tank. Two other fuelpumps (in series) draw fuel from the set tank and force thefuel through a primary strainer, two secondary filters, and acheck valve assembly, to the injection pump. In the highpressure 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 theengine. A small quantity of unused fuel is returned from theinjectors and injector pump to the fuel tank. A cam and gearon the camshaft drives the fuel injection pump. The geardrives the pump face gear, providing fuel distribution toeach cylinder in the proper order. The cam operates thepump plunger, pressurizing fuel to the nozzles. A controlsleeve meters fuel by controlling the length of time theplunger spill port is closed, maintaining pressure, and there-fore, the amount of fuel delivered in each stroke. The pintletype injection nozzles are conventional inward opening withadjustable opening pressure. They are factory adjusted toopen at 1900 to 1950 psi.Section II. MAINTENANCE OF FUEL TANK4-2. FUEL TANK.a. Inspect. On ASK equipped generators, refer toOperator and Organizational Maintenance Manual andremove left panel and side closure assemblies. Inspect thefuel tank per Operator and Organizational MaintenanceManual.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.WARNINGSObserve all safety precautions when solderingfuel tank. Avoid breathing fumes generated bylead soldering. Eye protection is required.Hot refueling of generators while they are oper-ating poses a safety hazard and should not beattempted. Hot engine surfaces and sparks pro-duced from the engine and generator circuitryare possible sources of ignition. Severe injury,death and/or damage to the equipment mayresult.(1) Repair leaks in fuel tank by soldering,(2) Clean repaired area with dry cleaning solventFederal 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 leftpanel and side closure assemblies. Install the fuel tank andcomponents per Operator and Organizational MaintenanceManual.(2) Fill tank with fuel oil.Change 74-1/(4-2 blank)
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