42164 Mercury SPRING

Recommended Actions
Fuel Transfer Pump Seal
Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to follow these inspection, maintenance and service instructions may cause personal injury or death.
Do not loosen any high pressure fuel lines when the engine is running. The high pressure in the fuel lines can cause personal injury or death. Wait 60 seconds after the engine has stopped to allow pressure to purge before any service or repair is performed on the engine fuel lines.
Check for fuel leakage around the shaft seal for the fuel transfer pump. Ensure that the weep hole is not plugged. If necessary, repair the fuel transfer pump or replace the fuel transfer pump.High Pressure Fuel Pump
Illustration 1 g01459809
Location of the plugs in the high pressure fuel pump and pump adapter (typical example)
(1) Plug in the high pressure fuel pump
(2) Plug in the fuel pump adapter Note: It is best to perform this test on a cold engine.Remove the plug from the bottom of the high pressure fuel pump. Remove the plug from the bottom of the fuel pump adapter. Expect that a small amount of engine oil will drain from the openings.Use the manual override for the fuel priming pump to run the pump in order to pressurize the fuel system. Allow the pump to run for at least five minutes while you monitor the drain holes in the pump and the adapter for leakage.Note: Your application may be equipped with a manual switch for the fuel priming pump. If a manual switch is not available, use the override in Cat ET to run the fuel priming pump.A pump that is in good repair will have no fuel leakage during the test.Fuel Injector's O-ring Seals
Pressurize the engine's fuel return line with 700 kPa (100 psi) of air pressure. Listen at each of the valve mechanism covers for an audible indication of air leakage.If leakage is found, remove the injector from the affected cylinder and visually inspect the injector's O-ring seals for damage. If damage is found, replace the damaged seals. Install the injector onto the engine and confirm that the repair has resolved the problem. Return the engine to service.If leakage is found and the O-rings are in good repair, there may be a problem with the injector. Replace the injector. Ensure that the new trim files are installed. Refer to Troubleshooting, "Injector Trim File - Install" for details. Use Caterpillar Electronic Technician (ET) to perform a "Fuel System Verification Test". Refer to Troubleshooting, "Injector Solenoid - Test" for details.If the leakage is not located with the previous test procedure, add the appropriate dye to the fuel tank. Run the engine at high idle for several minutes. Shut down the engine and remove the valve covers. Use a black light to check for traces of dye around each injector.If leakage is suspected for a specific injector, remove the injector from the affected cylinder and replace the damaged seals. Install the injector onto the engine and return the engine to service.Fuel Injector Tip
Use Cat ET to perform the "Cylinder Cutout Test" in order to identify any cylinders that may be overfueled. A fuel injector tip that is broken or fractured is a possible cause of a cylinder that is being overfueled. If a cylinder is identified by the test, Remove the injector and check the injector tip for damage. Check the fuel injector tip for cracks or breakage. If necessary, replace the suspect unit injector.Note: This fuel system utilizes flow limiter valves for each injector. An injector that is badly damaged may cause the flow limiter to trip. If the "Cylinder Cutout Test" indicates that a cylinder is not being fueled, check the condition of the fuel injector. If the fuel injector is in good repair, check the flow limiter valve for the affected cylinder. Refer to Systems Operation/Testing and Adjusting, "Fuel System" for information that is related to testing the high pressure fuel system.