KIT-GAS SPRING 1769170 - Caterpillar

Fuel System
SCHEMATIC OF THE FUEL SYSTEM
1. Fuel priming pump. 2. Fuel transfer pump. 3. Fuel injection pump. 4. Precombustion chamber. 5. Fuel supply line. 6. Primary fuel filter. 7. Bypass valve for fuel transfer pump. 8. Air vent valve. 9. Fuel filters. 10. Fuel manifold.This engine has a pressure type fuel system. There is a single injection pump and injection valve for each cylinder. The injection pumps (3) are in the pump housing on the right side of the engine. The injection valves are in the precombustion chambers (4) in the top left side of the cylinder head.The transfer pump (2) sends fuel from the fuel tank to the primary fuel filter (6). The primary fuel filter (6) removes the larger dirt particles from the fuel. Fuel goes from the primary fuel filter (6) to the fuel filters (9). The fuel filters (9) remove the smaller dirt particles from the fuel. Fuel goes from the fuel filters (9) to the fuel manifold (10) in the pump housing. This manifold is the source of fuel supply for each injection pump (3). The injection pumps (3) send fuel through high pressure fuel lines to the injection valves. The injection valves change the fuel to the correct fuel characteristic (spray pattern) for good combustion in the cylinders.The transfer pump (2) can supply more fuel than is necessary for injection, so a bypass valve (7) is used to control the pressure of the fuel in the fuel system.An air vent valve (8) in the fuel system is used to remove air from the fuel system. Air is removed by opening the air vent valve and putting pressure to the fuel system with the priming pump (1). Put pressure to the fuel system until a flow of fuel, free of air bubbles, comes from the vent line.Fuel Injection Pump Operation
Injection pump plungers (3) and lifters (6) are lifted by cams on camshaft (7) and always make a full stroke. The force of springs (5) hold the lifters (6) against the cams of the camshaft.Fuel from fuel manifold (1) goes through inlet passage (2) in the barrel and then into the chamber above plunger (3). During injection, the camshaft cam moves plunger (3) up in the barrel. This movement will close inlet passage (2) and push the fuel out through the fuel lines to the injection valves.The amount of fuel sent to the injection valves is controlled by turning plunger (3) in the barrel.
CROSS SECTION OF THE HOUSING FOR THE FUEL INJECTION PUMPS
1. Fuel manifold. 2. Inlet passage in pump barrel. 3. Pump plunger. 4. Gear segment. 5. Spring. 6. Lifter. 7. Camshaft.When the governor moves the fuel rack, the fuel rack moves gear segment (4) that is fastened to the bottom of plunger (3).Mechanical Governor
MECHANICAL GOVERNOR-LEFT SIDE VIEW (Typical Example)
1. High idle adjustment screw. 2. Low idle adjustment screw. 3. Stop. 4. Roller. 5. Spring. 6. Plunger. 7. Adjustment screw. 8. Lower housing. 9. Oil passage. 10. Weight. 11. Governor drive spindle.The governor