FUEL TRANSFER PUMP

TM-5-3805-263-14P-2 Grader Heavy Road Motorized Type I Nonsectionalized Type II Sectionalized Manual
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FUEL SYSTEM TM 5-3805-263-14&P-2 The 8N7005 Fuel Injection Nozzle can not be disassembled and no adjustments can be made. SYSTEMS OPERATION FUEL TRANSFER PUMP The fuel transfer pump is a two-piston pump that is moved by a cam (eccentric) on the camshaft for the fuel injection pump. The transfer pump is located on the right side of the fuel injection pump housing. When the camshaft turns, the cam lifts push rod (10) up. The push rod lifts large piston (9), push plate (6) and small piston (3). As the pistons move up, inlet check valve (5) and outlet check valve (8) close. Pumping check valve (7) in the large piston opens and fuel goes through the holes in the bottom of the large piston and fills the passages and chamber between the bottom of the large piston and outlet check valve (8). As small piston (3) moves up, the pressure of the fuel above the piston increases and flows out of the pump through outlet (4). As the camshaft continues to turn, the cam lowers push rod (10) down. Pumping spring (2) pushes small piston (3), push plate (6) and large piston (9) down. When the piston moves down, inlet check valve (5) and outlet check valve (8) open. Pumping check valve (7) in the large piston closes and the pressure of the fuel below the check valve increases. Fuel now flows through the outlet check valve. A part of the fuel goes through outlet (4) and the remainder goes to the area above small piston (3). As the large piston moves down, fuel from the fuel tank is pulled through inlet check valve (5) into the area between the large and small piston. The pump is now ready to start a new cycle. Bypass valve (1) controls the outlet pressure of the fuel. If the fuel pressure goes beyond 170 to 280 kPa (25 to 40 psi), the bypass valve opens and fuel flows to the inlet of the pump. OIL FLOW FOR FUEL PUMP AND GOVERNOR Oil from the side of the cylinder block goes to support (9) and into the bottom of front governor housing (4). The flow of oil now goes in three differ- ent directions. A part of the oil goes to the rear camshaft bearing in fuel pump housing (5). The bearing has a groove around the inside diameter. Oil goes through the groove and into the oil passage in the bearing surface (journal) of camshaft (7). A drilled passage through the center of the camshaft gives oil to the front camshaft bearing and to the thrust face of the cam- shaft drive gear. Drain hole (6) in the front of ‘fuel pump housing (5) keeps the level of the oil in the housing even with the center of the camshaft. The oil returns to the oil pan through the timing gear housing. 1-8

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