0340216 JOHNSON WATER TUBE

Fuel System
SCHEMATIC OF THE FUEL SYSTEM
1. Fuel priming pump. 2. Fuel filter bypass valve. 3. Fuel filter. 4. Fuel injection pump. 5. Precombustion chamber. 6. Fuel supply line. 7. Primary fuel filter. 8. Fuel transfer pump. 9. Bypass valve for fuel transfer pump. 10. Fuel manifold.This engine has a pressure type fuel system. There is an injection pump and injection valve for each cylinder. Fuel injection pumps (4) are in the pump housing on the right side of the engine. The injection valves are in precombustion chambers (5) in the top left side of the cylinder head.Fuel transfer pump (8) sends fuel from the fuel tank to primary fuel filter (7). Primary fuel filter (7) removes the larger dirt particles from the fuel. Fuel goes from primary fuel filter (7) to fuel filter (3). Fuel filter (3) removes the smaller dirt particles from the fuel. Fuel goes from fuel filter (3) to fuel manifold (10) in the pump housing. This manifold is the source of fuel supply for each injection pump (4). Fuel injection pumps (4) 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.Fuel transfer pump (8) can supply more fuel than is necessary for injection, so a bypass valve (9) is used to control the pressure of the fuel in the fuel system.An air vent valve 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 fuel 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
The injection pump plunger (5) and lifter assembly (8) are lifted by the cam on camshaft (9) and make a full stroke every time. The force of the spring (6) holds the lifter assembly (8) against the cam of the camshaft (9).Fuel from fuel manifold (3) goes through inlet passage (2), in the barrel and then into the chamber above the plunger (5). During injection, the camshaft cam moves plunger (5) up in the barrel. This movement of plunger (5) closes inlet passage (2) and pushes the fuel out past the check valve (1) through the fuel lines to the injection valves.Injection starts when the top of the plunger (5) goes past and closes the inlet port (2). The point of injection is in relation to crankshaft position and is controlled by the thickness of spacer (10). A thicker spacer (10) makes the point of injection later and a thinner spacer (10) makes the point of injection sooner.The amount of fuel sent by the pump per stroke of the plunger (5) is changed by turning the plunger (5) in the barrel. Governor action moves the rack (7) which turns the pump gear segment (4) on the bottom of the plunger (5).
CROSS SECTION OF THE HOUSING FOR THE FUEL INJECTION PUMPS
1. Check valve. 2. Inlet passage in pump barrel. 3. Fuel manifold. 4. Gear segment. 5. Pump plunger. 6. Spring. 7. Fuel rack. 8. Lifter assembly. 9. Camshaft. 10. Spacer.Fuel Injection Valve
CROSS SECTION OF FUEL INJECTION VALVE
1. Fuel injection line. 2. Nut. 3. Glow plug. 4. Body. 5. Nozzle assembly. 6. Precombustion chamber.High pressure fuel from the injection pumps goes through the fuel injection lines to the fuel injection valves. As this high pressure fuel goes into the nozzle assembly (5), the check valve in the nozzle assembly opens and the fuel goes into the precombustion chamber (6). The injection valve changes the fuel to the correct fuel characteristics (spray pattern) for good combustion in the cylinders.Hydra-Mechanical Governor
The governor control is connected to the control lever assembly on the engine governor. The governor controls the amount of fuel needed to keep the desired engine rpm (governed rpm).The governor has governor weights (12) driven by the engine, governor spring (5), valve (14) and piston (15). The valve and piston are connected to fuel rack (18). The pressure oil for the governor comes from the engine oil pump. Pressure oil goes through passage (17) and around sleeve (16). The governor control controls only the compression of governor spring (5). Compression of the spring constantly pushes to give more fuel to the engine. The force of rotation (centrifugal force) of governor weights (12) is constantly pulling to get a reduction of fuel to the engine. When these two forces are in balance, the engine runs at the desired rpm.
CROSS SECTION OF THE HYDRA-MECHANICAL GOVERNOR
1. Collar. 2. Speed limiter plunger. 3. Lever assembly. 4. Seat. 5. Governor spring. 6. Thrust bearing. 7. Oil passage. 8. Drive gear for weight assembly. 9. Cylinder. 10. Bolt. 11. Spring seat. 12. Governor weights. 13. Spring. 14. Valve. 15. Piston. 16. Sleeve. 17. Oil passage. 18. Fuel rack.The governor valve is shown here in the position when the force of rotation of the governor weights and the force of the governor spring are in balance.When there is an increase in engine load, there is a decrease in engine rpm and the rotation of governor weights (12) is slower. (The governor weights will move toward each other.) Governor spring (5) moves valve (14) forward. When valve (14) moves forward, an oil passage around valve (14) opens to pressure oil. Oil then flows through passage (7) and fills the chamber behind piston (15). This oil pushes the piston and rack forward to give more fuel to the engine. Engine rpm goes up until the force of rotation of the governor weights is large enough to be in balance with the force of the governor spring.When there is a reduction in engine load, there is an increase in engine rpm and the rotation of governor weights (12) is faster. This moves valve (14) backwards letting the oil behind piston (15) go through an open passage at the rear of the piston. The pressure oil between