19299A 1 Mercury VENT

Illustration 1 g01247195
Fuel injection pump and governor drive group (typical example)
The part number is stamped in this location.
Table 1
3412C Fuel System With Caterpillar Dashpot Governors    
Engine Arrangement     In. Pump & Governor Group or Drive     Injection Pump    
148-3590     4W-8296     4N-1101    
148-3592    
148-3594    
166-8581    
166-8583    
166-8585    
148-3598     7W-7131    
148-3600    
166-8589    
166-8591    
186-4817    
149-7505     131-3239    
186-4816     108-3698    
186-4819     108-3697    
148-3591     4W-6074     4W-6073    
148-3593    
148-3595    
148-3599    
148-3601    
166-8582    
166-8584    
166-8586    
166-8590    
166-8592    
171-5336    
187-0557    
189-8854    
149-7506     131-3240     131-3281    Fuel System
Either too much fuel for combustion or not enough fuel for combustion can be the cause of a problem in the fuel system. It is difficult to evaluate the source of the problem, especially when smoke rises from the exhaust. Therefore, work is often done on the fuel system when the problem is really with some other part of the engine.When noticeable smoke rises from the exhaust, this problem can be caused by a worn unit injector. This unusual smoke can also be caused by one or more of the reasons that follow:
Not enough air for good combustion
Oil leakage into combustion chamber
Not enough compressionFuel System Inspection
A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.
Check the fuel level in the fuel tank. Inspect the cap for the fuel tank. Make sure that the vent is not filled with dirt.
Check the fuel lines for fuel leakage. Make sure that none of the fuel lines have a restriction or a faulty bend.
Install a new fuel filter. Clean the primary fuel filter.
Remove any air that may be in the fuel system.If there is air in the fuel system, use the priming pump to open the drain valve on the fuel injection pump housing. Drain the fuel system until fuel without air flows from the drain line.Checking Engine Cylinders Separately
If any of the following conditions occur, check the individual engine cylinders:
The engine runs rough.
The engine misfires.
The exhaust system blows out black smoke.Use this procedure to check the engine cylinders separately:
Run the engine at the roughest speed.
Loosen the fuel line nut at a fuel injection pump. This will stop the flow of fuel to that engine cylinder.After you shut off an engine cylinder's fuel flow, the engine should run more roughly.
Tighten the fuel line nut.
Repeat this maneuver with each engine cylinder in sequence until you discover a loosened fuel line that does NOT affect the engine's performance.
When you find the engine cylinder that does NOT affect the engine's performance, perform the following operations:
Test the fuel injection pump.
Test the fuel injection valve.When an engine runs at low idle rpm, the temperature of an exhaust manifold can also indicate the condition of a fuel injection valve. A low temperature indicates that no fuel is reaching the cylinder. This can possibly signify that the fuel injection valve has a defect.When an engine runs at low idle rpm and the temperature of an exhaust manifold is at an extra high temperature, too much fuel is probably flowing into the engine cylinder. This can also signify that the fuel injection valve has a defect.The most common defects on fuel injection valves include the following defects:
Any carbon on the tip of a nozzle
Any carbon in the nozzle orifice
Orifice wear
Dirty nozzle screenTesting Fuel Injector Nozzles
The injectors must be off of the engine before being tested.Note: Refer to Special Instruction, SEHS7292, "Use Of 5P-4150 Nozzle Assembly" for more information.Fuel Injection Lines
Fuel from the fuel injection pumps is sent through the fuel injection lines to the fuel injection valves.Each fuel injection line of an engine has a special design. Each fuel injection line must be installed in a certain location. When fuel injection lines are removed from an engine, put identification marks or put tags on the fuel lines as the lines are removed. This will allow the lines to be installed in the correct location.The nuts that hold a fuel injection line to an injection valve and to an injection pump must be kept tight. Tighten the fuel line nuts to 40 7 N m (30 5 lb ft).Fuel Bypass Valve
The fuel bypass valve controls fuel pressure to the fuel injection pump. At full speed, the pressure is limited to 230 35 kPa (33 5 psi).Finding the Top Center Position for No. 1 Piston
Table 2
Tools Needed    
9S-9082     Engine Turning Tool     1    Note: The starting position for all timing procedures is with the No. 1 piston at the top center position on the compression stroke.