0341653 JOHNSON BUMPER, Cover

Engine Design
CYLINDER, VALVE AND INJECTION PUMP LOCATIONBore ... 5.40 in.(137.2 mm)Stroke ... 6.00 in.(152.4 mm)Number and Arrangement of Cylinders ... V-8Firing Order (Injection Sequence) ... 1, 8, 4, 3, 6, 5, 7, 2Rotation of Crankshaft (when seen from flywheel end) ... counterclockwiseRotation of Fuel Pump Camshaft (when seen from pump drive end) ... counterclockwise Front end of engine is opposite to flywheel end. Left side and right side of engine are as seen from flywheel end. No. 1 cylinder is the front cylinder on the left side. No. 2 cylinder is the front cylinder on the right side.Fuel System
This engine has a pressure type fuel system. There is one injection pump and one injection valve for each cylinder. The injection pumps are in injection pump housing (5) on the top of the engine. Injection valves (6) are in the precombustion chambers or adapters (for engines with direct injection) under the valve covers.Fuel is pulled from fuel tank (11) through primary fuel filter (10) by fuel transfer pump (9). The transfer pump sends fuel through secondary fuel filter (8) to the manifold of the fuel injection pump housing.Fuel in the manifold of the injection pump housing is the supply for the injection pumps. Some of the fuel in the manifold is constantly sent through an orifice in the fitting that connects the return line to the manifold. The orifice controls the pressure in the manifold and the amount of fuel that returns to the tank. The constant flow of fuel back to the tank removes air from the system.
FUEL SYSTEM SCHEMATIC
1. Inlet line. 2. Adapter with orifice. 3. Return line. 4. Location for pressure measurement. 5. Injection pump housing. 6. Injection valve. 7. Priming pump. 8. Secondary fuel filter. 9. Fuel transfer pump. 10. Primary fuel filter. 11. Fuel tank.The injection pumps are in time with the engine. They send fuel to the injection valves under high pressure. When the fuel pressure at the injection valve is high enough the valve opens and sends fuel into the precombustion chamber or directly into the cylinder on direct injection engines.
LOCATION OF FUEL SYSTEM COMPONENTS
1. Inlet line. 2. Adapter with orifice. 3. Return line. 4. Location for pressure measurement. 5. Injection pump housing. 9. Fuel transfer pump.Fuel transfer pump (9) has a bypass valve and a pressure relief valve. The bypass valve makes it possible for the priming pump to send fuel through the transfer pump. The pressure relief valve controls the maximum pressure of the fuel. When the pressure gets too high the valve opens and some of the fuel goes back to the inlet side of the pump.When there is air on the inlet side of the fuel system use priming pump (7). Operation of the priming pump fills the system with fuel. This forces the air back into the tank.Air can be removed from the fuel injection lines by loosening a fuel injection line nut (one at a time) at the valve cover base adapter. On PC Engines use the priming pump to remove the air. On DI Engines use the starter motor to turn the engine until fuel without air flows from the loosen nut. Tighten the nuts after air has been removed. Because of the check assemblies in the injection pump outlets for the DI engine, the priming pump will not give enough pressure to remove air from the fuel injection lines.Fuel Injection Pump
The rotation of the cams on the camshaft (12) cause lifters (9) and pump plungers (5) to move up and down. The stroke of each pump plunger is always the same. The force of springs (6) hold lifters (9) against the cams of the camshaft.The pump housing is a "V" shape (similar to the engine cylinder block), with four pumps on each side.When the pump plunger is down, fuel from fuel manifold (1) goes through inlet passage (2) and fills the chamber above pump plunger (5). As the plunger moves up it closes the inlet passage.The pressure of the fuel in the chamber above the plunger increases until it is high enough to cause check valve (3) to open. Fuel under high pressure flows out of the check valve through the fuel line to the injection valve until the inlet passage opens into pressure relief passage (4) in the plunger. The pressure in the chamber decreases and check valve (3) closes.The longer the inlet passage is closed the larger the amount of fuel which will be forced through check valve (3). The period for which the inlet passage is closed is controlled by the pressure relief passage. The design of the passage makes it possible to change the inlet passage closed time by rotation of the plunger. When the governor moves fuel racks (8) they move gears (7) that are fastened to plungers (5). This causes a rotation of the plungers.The governor is connected to the left rack. The spring load on lever (11) removes the play between the racks and link (10). The fuel racks are connected by link (10). They move in opposite directions (when one rack moves in, the other rack moves out).
CROSS SECTION OF THE FUEL INJECTION PUMP HOUSING (Pumps Illustrated for DI Engines)
1. Fuel manifold. 2. Inlet passage. 3. Check valve. 4. Pressure relief passage. 5. Pump plunger. 6. Spring. 7. Gear. 8. Fuel rack (left). 9. Lifter. 10. Link. 11. Lever. 12. Camshaft.Fuel Injection Valves - (On Earlier Engines)
Fuel, under high pressure from the injection pumps, is sent through the injection valves. The injection valves change the fuel to the correct fuel characteristic (spray pattern) for good combustion in the cylinders.The fuel injection valves are installed in the precombustion chambers in engines equipped with precombustion chambers. An adapter takes the place of the precombustion chamber in engines equipped with direct injection. The precombustion chambers or adapters are installed in the cylinder heads.Fuel Injection Nozzles - (On Later Engines)
The fuel injection nozzle goes through the cylinder head into the combustion chamber. The fuel injection pump sends fuel with high