NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2910-212 FUEL BACKFLOW VALVE AND FUEL FILTERS OVERHAUL—Continued 0032 00 INSPECTION – Continued 4. Fuel Backflow Valve. Inspect the fuel backflow valve using the procedures outlined below. a. Fill fuel backflow valve with test fluid, MIL-PRE-7024E, Type II, and apply a pressure of 1/2 psi to the port marked FREE FLOW (fuel inlet from primary fuel filter). The backflow valve must open at this pressure. Valve operation can be determined when fluid flows from the fuel pump outlet port (Figure 1). b. Apply a pressure of 85 to 95 psi to the heater pump inlet port. The check ball must bypass fluid at this pressure. Adjust socket head adjusting screw to obtain this opening pressure. c. Plug the fuel pump outlet port and the heater pump outlet port. Then apply a pressure of 100 psi at the heater pump inlet port. There should be no fuel leakage from the port marked FREE FLOW. d. If the valve leaks or fails to pass either test, refer to Repair section below for repair instructions. Figure 1. Fuel Backflow Valve Flow Diagram. 0032 00-3 Change 1