84842M Mariner HOUSING, LOWER MOUNT - PORT

Illustration 1 g00332354
Fuel flow schematic (1) Fuel inlet line for the injection pump housing (2) Damper (3) Adapter with orifice (4) Injection pump housing (5) Fuel return line (6) Injection valve (7) Junction block (8) Fuel priming pump (9) Bypass valve (10) Fuel tank (11) Fuel supply line (12) Primary fuel filter (13) Fuel pressure gauge (14) Main fuel filters (15) Pressure relief valve (16) Fuel transfer pumpThese engines have a pressure type fuel system. There is one injection pump and one fuel injector nozzle for each cylinder. The injection pumps are in the pump housing (4) on the top front of the engine. The fuel injection nozzles are located in the fuel injection adapters. The fuel injection adapters are under the valve covers.The fuel transfer pump (16) pulls the fuel from the fuel tank (10) through the primary fuel filter (12). The fuel flows from the primary fuel filter to the fuel priming pump (8) and through the main fuel filters (14). The fuel then flows to the manifold of the injection pump housing. The fuel in the manifold of the injection pump housing flows to the injection pumps. The injection pumps are in time with the engine. The injection pumps push fuel at a very high pressure to the injection valves (6).
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Location of the fuel system components (typical example) (1) The fuel inlet line for the injection pump housing (2) Damper (3) Adapter with orifice (5) Fuel return line (11) Fuel supply line (16) Fuel transfer pump (17) The fuel outlet line from the transfer pump and the inlet line to the main filters (18) The nut for a fuel injection line at the injection pump (19) The fuel manifold across the injection pump housing (20) Adapter through the valve cover baseA damper (2) is located on the inlet elbow of the fuel manifold (19). The damper (2) reduces the shock loads that are caused by the injection pumps. Some of the fuel in the fuel manifold is constantly sent through a restriction orifice (3). This removes air from the system. This restriction keeps the fuel pressure high. The restriction also controls the amount of fuel that goes back to the fuel tank through the return line (5) .The fuel priming pump (8) is used to fill the system with fuel. The fuel priming pump also removes air from the low pressure side of the fuel system. The low pressure side of the fuel system consist of the fuel filter, the fuel lines and components.
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The location of the fuel system components (typical example) (1) The fuel inlet line for the injection pump housing (5) The fuel return line (7) Junction block (8) Fuel priming pump (11) Fuel supply line (14) Main fuel filters (17) The fuel outlet line from the transfer pump and the inlet line to the main filtersThe fuel transfer pump has a bypass valve and a check valve. The bypass valve controls the maximum pressure of the fuel. The extra fuel goes to the inlet of the pump. The check valve allows the fuel from the tank to go around the transfer pump gears when the priming pump is used.Fuel Injection Pump
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The cross section of the fuel injection pump housing (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) CamshaftThe rotation of the cams on the camshaft (12) cause the lifters (9) and the pump plungers (5) to move up and down. The stroke of each pump plunger is always the same stroke. The force of the springs (6) hold the lifters (9) against the cams of the camshaft.The pump housing is in a shape of a V. The shape is similar to the engine cylinder block. There is the same number of pumps on each side.When the pump plunger moves down, the fuel from the fuel manifold (1) flows through the inlet passage (2). The fuel then fills the chamber that is above the pump plunger (5). When the plunger moves up, the plunger closes the inlet passage.The pressure of the fuel in the chamber above the plunger increases until the pressure is high enough to cause the check valve (3) to open. The high pressure fuel flows through the check valve, through the fuel line and to the injection valve. The high pressure fuel flows into the inlet passage which opens into the pressure relief passage (4) that is in the plunger. The pressure in the chamber decreases and check valve (3) closes.The amount of fuel that is forced through check valve (3) is determined by the length of time that the inlet passage (2) is closed. The pressure relief passage (4) is used in order to control the state of the inlet passage. The design of the pressure relief passage allows the rotation of the plunger to control fuel metering for each pump. When the governor moves the fuel racks (8), the fuel racks move the gears (7) that are fastened to the plungers (5). This causes a rotation of the plungers.The governor is connected to the left rack. The play between the racks and link (10) is controlled by a spring that loads lever (11). The fuel racks are connected by the link (10). The fuel racks move in opposite directions. When one rack moves in, the other rack moves out.Fuel Injection Nozzles
The fuel injection nozzle is installed into an adapter through the cylinder head into the combustion chamber. The fuel injection pump sends fuel with high pressure to the fuel injection nozzle. Then, the fuel is made into a fine spray for good combustion.
Illustration 5 g00354279
Fuel injection nozzle (typical example) (1) Carbon dam (2) Seal (3) Passage (4) Filter screen (5) Inlet passage (6) Orifice (7) Valve (8) Diameter (9) SpringSeal (2) is positioned against the nozzle adapter. This prevents leakage of compression from the cylinder. Carbon dam (1) keeps carbon out