16124 Mercury BUSHING, GEAR HOUSING

Fuel Supply
Air in the fuel system
Fuel supply valve (if applicable)
Improperly operating fuel pressure regulator
Fuel level
Blockage of the vent port on the fuel cap
Proper operation of the electric fuel priming pump
Diagnostic codes for the fuel pump relayEvent Codes
Check for intermittent event codesDiagnostic Codes
Check for intermittent diagnostic codesFlash File
Noncurrent flash fileThrottle Signal
Intermittent throttle signalInjection Actuation Pressure
Engine oil level
Proper operation of the injection actuation pressure control valveAir Inlet and Exhaust System
Restriction in the air inlet and exhaust systemRecommended Actions
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high engine speed, full load and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.Air in the Fuel System
Check for air in the fuel system.Fuel Supply Valve (if applicable)
Ensure that the fuel supply valve (if equipped) is in the full OPEN position.Improperly Operating Fuel Pressure Regulator
An improperly operating fuel pressure regulating valve may cause low fuel pressure. If a problem is suspected, inspect the return fuel pressure regulating valve. Clean any contamination or debris that may keep the regulating valve from operating properly. If debris is present, find the source of the contamination. Replace the return fuel pressure regulating valve if the valve is worn or damaged.Fuel Level
Visually inspect the fuel level in the fuel tank. Ensure that the fuel tank contains enough fuel in order to operate the engine.Blockage of the Vent Port on the Fuel Cap
Remove the fuel tank cap from the fuel tank. Check the vent port that is in the cap for debris. Clear any restrictions with compressed air.Note: Do not allow debris to enter the fuel tank while you clean the cap. Damage to the fuel system will occur.Proper Operation of the Electric Fuel Priming Pump
The electric fuel priming pump provides the fuel to the low pressure fuel system. When the keyswitch is turned to the ON position, the electric fuel priming pump runs for two minutes. This should prime the fuel system. If the fuel system is not fully primed, turn the keyswitch to the OFF position and repeat the sequence.When the engine is cranking or running the electric fuel priming pump will run continuously. There is no fuel transfer pump in the unit injector hydraulic pump.Prime the fuel system if any of the following procedures have been performed:
Replacement of the fuel filters
Service on the low pressure fuel supply circuit
Replacement of unit injectorsStart the engine. Run the engine at low idle. Use Caterpillar Electronic Technician (ET) to monitor the fuel pressure for the engine.Check the value of the fuel pressure while the engine is at low idle. Ensure that the value of the fuel pressure is reasonable. If the value of the fuel pressure fluctuates, there may be blockage to the intake side of the electric fuel priming pump.Inspect the lines to the electric fuel priming pump. Check the fuel lines for the following: kinked fuel suction line, collapsed lines and contamination.Diagnostic Codes for the Fuel Pump Relay
Use Cat ET to check for diagnostic codes for the fuel pump relay. If diagnostic codes for the fuel pump relay are logged or active, refer to Troubleshooting, "Fuel Transfer Pump - Test".Check for Intermittent Event Codes
Certain event codes may derate engine power. Connect Cat ET and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.Check for Intermittent Diagnostic Codes
Certain diagnostic codes may cause poor performance. Connect Cat ET and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.Noncurrent Flash File
Verify that the latest flash file is installed in the Electronic Control Module (ECM).Intermittent Throttle Signal
Monitor the status for "Throttle Position" on Cat ET. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed. Refer to Troubleshooting, "Speed Control (Switch) - Test".Engine Oil Level
Check the engine oil level. Engine oil supplies the injection actuation pressure circuit. The engine oil must be kept at the proper level for fuel injection.Proper Operation of the Injection Actuation Pressure Control Valve
Check the operation of the injection actuation pressure control valve. Refer to Troubleshooting, "Injection Actuation Pressure Control Valve - Test".
Check the injection actuation pressure. Refer to Troubleshooting, "Injection Actuation Pressure - Test". Restriction in the Air Inlet and Exhaust System
Ensure that the turbocharger is operating correctly. Periodic inspection and cleaning is recommended for the turbocharger compressor housing (inlet side). Refer to Systems Operation/Testing and Adjusting for the procedure to inspect the turbocharger.Check the air inlet and exhaust systems for restrictions and for leaks. Refer to Systems Operation/Testing and Adjusting for the procedure to inspect the system. Look for an indication of the warning lamp or restriction indicators that are tripped if the filters are equipped with these devices. These indicators are associated with plugged filters. Replace the plugged air filters or clean the plugged air filters per the guidelines of the Operation and Maintenance Manual. Repair any leaks that are found in the system.