838780 Volvo.Penta Coolant pipe

Illustration 1 g00757805
Typical example of a basic fuel system diagram
(1) Fuel return line from fuel injection pump to fuel filter base
(2) Fuel line to fuel injection pump
(3) Fuel supply line from fuel filter base to fuel injection pump
(4) Fuel filter base
(5) Fuel line from fuel transfer pump to fuel filter base
(6) Fuel transfer pump
(7) Fuel line from fuel tank to fuel transfer pump
(8) High pressure fuel line to fuel injection nozzles
(9) Fuel injection pump
(10) Fuel return line from fuel injection nozzles to fuel filter base
(11) Fuel injection nozzle
(12) Fuel return line from fuel filter base to fuel tank
(13) Fuel tank While the engine is running, fuel is pulled from fuel tank (13) by fuel transfer pump (6). Fuel transfer pump (6) sends the fuel at a low pressure to fuel filter base (4). The fuel then passes through fuel supply line (3) to fuel injection pump (9). Fuel injection pump (9) sends fuel through high pressure fuel lines (8) to each fuel injection nozzle (11). Fuel injection nozzle (11) sprays fuel into the cylinder. The fuel that is not used by the fuel injection nozzles passes through fuel return line (1) from the fuel injection pump to fuel filter base (4). The fuel is then sent back to the fuel injection pump through fuel line (10).Leakage from fuel injection nozzle (11) flows through fuel return line (10) into the top of fuel filter base (4). The fuel then returns to fuel tank (13) through fuel return line (12).Fuel injection pump (9) uses fuel for lubrication. Fuel is supplied to the fuel injection pump through fuel line (2) and the fuel is returned to the fuel filter base through fuel return line (1). The precision parts of the fuel injection pump are easily damaged. Therefore, the engine must not be started until fuel injection pump (9) is full of fuel that is free of air.The system must be primed when any part of the system is drained of fuel for the following reasons:
The fuel filter is replaced.
A fuel line is removed.
The inspection cover on the fuel injection pump is removed for service or repair.Refer to the Systems Operation, Testing and Adjusting Module, "Fuel System - Prime" topic for the correct procedure.There is a small screen in fuel transfer pump (6). The fuel transfer pump also has a manual lever that is used to prime the fuel system. There is a banjo bolt on the front of fuel filter base (4) that is used to release air in the system.An air inlet heater is installed in the inlet manifold. The air inlet heater is controlled by a remote mounted control switch.
Ensure that there is fuel flow through the valve body of the cold start heater, or damage may occur. The fuel supply line to the inlet air heater must also be free of air, or damage may occur. An inlet air heater that is damaged will let fuel drain into the inlet manifold when the engine is running and could cause exhaust smoke.
Fuel Injection Nozzle
Illustration 2 g00296969
Typical example of a fuel injection nozzle
(1) Fuel return
(2) Cap nut
(3) Fuel inlet
(4) Pressure adjusting screw
(5) Pressure spring
(6) Body
(7) Spindle for spring
(8) Retaining nut for the nozzle
(9) Needle valve
(10) Nozzle
(11) Orifices
(12) Sealing washer Fuel that is under high pressure from the fuel injection pump flows through the orifice in fuel inlet (3). The fuel flows around needle valve (9) and into nozzle (10). The fuel applies pressure against needle valve (9) and pressure spring (5). When the force of the fuel pressure is greater than the force of pressure spring (5), needle valve (9) will raise. Fuel under high pressure will pass through orifices (11) into the cylinder. The force that is created by the pressure of the fuel then becomes less than pressure spring (5) and needle valve (9) will move quickly to the closed position.Needle valve (9) has a close fit with the inside of nozzle (10). This fit creates a positive seal for needle valve (9).When the fuel is sent into the cylinder, a small quantity of the fuel will leak past the valve guide. This fuel provides lubrication to the moving parts of the fuel injection nozzle. The fuel then passes through a leak off passage in body (6) to fuel return (1) to the fuel tank.Fuel Injection Pump
Illustration 3 g00531642
Typical example of the fuel injection pump components
(1) Control lever
(2) Flyweights
(3) Flow adjusting screw
(4) Drive shaft
(5) Governor lever
(6) Solenoid
(7) Housing for delivery valves
(8) Control sleeve
(9) Feed pump
(10) Holder for roller
(11) Plunger
(12) Cam disk
(13) Timer
(14) Plunger spring
(15) Delivery valve The fuel injection pump is fully closed and pressurized. The fuel injection pump sends the correct amount of high pressure fuel through the fuel injection nozzles to the individual cylinders at the correct time. The correct time is near the end of the compression stroke. The fuel injection pump measures the amount of fuel that is delivered to the fuel injection nozzles. The amount of fuel is controlled by adjusting the governor setting, the position of the accelerator, or the throttle control.The fuel lines to the fuel injection nozzles are equal lengths. Fuel lines that are equal length ensure even pressure and the correct injection timing at each fuel injection nozzle.During operation, excess fuel is used for cooling and lubrication. The fuel flows through the housing of the fuel injection pump and back to the fuel tank. Return lines also carry away air that is trapped in the fuel injection nozzles or in the housing of the fuel injection pump.
Illustration 4 g00531644
Typical example of a cross section view of a fuel injection pump
(4) Drive shaft
(6) Solenoid
(8) Control sleeve
(12) Cam disk
(14) Plunger spring
(15) Delivery valve
(16) Gear Cam disk (12) is driven from the engine by gear (16). Cam disk (12) is attached to plunger (11) that has dual motion. The lobes on cam disk (12) cause the plunger to reciprocate. The reciprocating motion pressurizes the fuel. This reciprocating motion brings the fuel into the fuel injection pump. Plunger (11) rotates with cam disk (12). This aligns the