0318174 JOHNSON TIMING POINTER, Manifold

Illustration 1 g02264199
Typical example
Fuel from the tank (A) leaves the primary fuel filter (2) and then passes to the diaphragm type fuel transfer pump (1). The fuel transfer pump (1) is driven by an eccentric on the camshaft. Fuel leaves the fuel transfer pump (1) under pressure and passes through the secondary fuel filter (3) to the fuel injection pump (5). The secondary fuel filter (3) is a twin filter.Extra fuel is circulated through the injection pump (5). The extra fuel is then returned to the fuel tank.A fuel heater or cooler may be installed between the filter head and filter canister.The fuel injection pump (5) sends fuel through the fuel injection lines (4) to each of the fuel injection nozzles (7). The fuel injection lines (4) to the fuel injection nozzles (7) are equal lengths. This ensures even pressure and correct injection timing at each fuel injection nozzle (7). The fuel injection nozzle (7) sprays the fuel into the cylinder. Fuel that is not injected flows through the fuel return line (6) to the top of the secondary fuel filter. The fuel then flows back to the fuel tank (B).The engine must not be started until the fuel injection pump is full of fuel that is free of air. The fuel injection pump requires fuel for lubrication. The precision parts of the pump are easily damaged without lubrication.The fuel system must be primed when any of the following conditions occur:
The fuel filter is changed.
The fuel line is removed.
The fuel injection pump is removed.Fuel System Components
Fuel Injection Pump
General Operation
Illustration 2 g01352237
Typical example
(1) Fuel injection pump
(2) Locking screw
(3) Washer The fuel injection pump is a pressurized system that is totally enclosed. The pump sends the correct amount of fuel under high pressure at the correct time through the fuel injection nozzles to the individual cylinders. The fuel injection pump regulates the amount of fuel that is delivered to the fuel injection nozzles. This action controls the engine rpm by the governor setting or the position of the throttle control.The Delphi DP310 fuel injection pump must be serviced by an authorized Delphi technician. For repair information, contact your Caterpillar dealer. High idle and low idle of the fuel injection pump are factory set. Idle adjustments cannot be made to the fuel pump. The fuel injection pump has a boost control and an engine stop solenoid. The Delphi DP310 fuel injection pump has a feature that vents air from the pump.The fuel injection pump has a cold starting aid. The cold starting aid advances the timing of the pump when the engine is cold. The cold starting aid is electrically operated.Cold Start Advance Unit
The cold start advance unit holds the timing of the fuel injection pump in an advance position when the engine is cold.The coolant switch for the cold start advance unit is on the rear of the timing case on the left side of the engine.When the engine is cold, the sender unit is energized in order to advance the fuel injection pump timing for the cold start operation. When the correct temperature is achieved the sender unit is de-energized and the fuel injection pump timing is returned to the normal operating position.If the switch fails in the closed position, the engine will run with advanced fuel injection timing. The engine will have higher cylinder pressure and engine damage may result.If the switch fails in the open position the engine will run with the fuel injection timing in the normal operating position. The engine will be more difficult to start. When the engine is cold the engine might emit white smoke.Fuel filters
There are three types of fuel filter element that may be installed to the engine.The separate element type where the fuel filter element is held between the fuel filter base and the bottom cover. The fuel filter can have two elements.The canister type where the fuel filter element has an internal thread at the top and is fastened to a threaded adaptor in the fuel filter base.A fuel filter with a quick release canister. The fuel filter can have two canisters. Some engines are fitted with a primary fuel filter of the same type. This fuel filter is fitted next to the main fuel filter, but connected in the fuel system before the fuel transfer pump. It is important to ensure that the main fuel filter and the primary fuel filter are installed in the correct positions.