818934 50 Mercury SCREW, (M8 x 50)

The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Probable Causes
Diagnostic codes
Event codes
Programmable parameters
Cold mode
High exhaust temperature
Throttle signal
Rated fuel position and/or FRC fuel position
Boost pressure sensor
Fuel supply
Air inlet and exhaust system
Accessory equipmentRecommended Actions
Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect the Caterpillar Electronic Technician (ET) and check for active codes and logged codes. Troubleshoot any codes that are present before continuing with this procedure.Programmable Parameters
Check the following parameters on Cat ET:
"Throttle Position Sensor"
"Desired Speed Input Configuration"
"Direct Fuel Control Mode"Determine the type of throttle that is used in the application. Program the parameters to match the type of throttle that is used. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test" for more information.Note: The engine will have poor performance if the parameters are not programmed correctly.Cold Mode
Use the electronic service tool to verify that the engine has exited cold mode. A status flag will appear if the engine is operating in cold mode. This may limit engine speed.High Exhaust Temperature
The engine may be derated due to high exhaust temperature. Connect Cat ET to the service tool connector. Check for an active engine derate on the status screens.Throttle Signal
Connect Cat ET to the service tool connector. View the status for the throttle position on the status screen. Operate the throttle from the Low Idle position to the High Idle position. The status should be 0 percent at low idle and the status should be 100 percent at high idle. If the status can not operate in the full range, refer to Troubleshooting, "Throttle Position Sensor - Calibrate".Diagnostic codes that are related to the J1939 data link will prevent correct operation of the throttle if the throttle position is transmitted over the data link. If there is a problem with the data link, the engine will remain at low idle until the data link is repaired.Boost Pressure Sensor, Rated Fuel Position and/or FRC Fuel Position
With the engine at full load, monitor "Fuel Position" and "Rated Fuel Limit" on the status screen. If "Fuel Position" does not equal "Rated Fuel Limit" then check air inlet manifold pressure.
Verify that there are no active diagnostic codes that are associated with the boost pressure sensor or with the atmospheric pressure sensor.
Monitor boost pressure and atmospheric pressure on the status screen for normal operation. Note: Atmospheric pressure is not a default parameter on a status screen. You must manually select the parameter for the atmospheric pressure in order to monitor the atmospheric pressure sensor.Fuel Supply
Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
Check the fuel tank for foreign objects which may block the fuel supply.
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 injectorsNote: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel.
Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
Check the fuel pressure during engine cranking. Check the fuel pressure on the outlet side of the fuel filter. Refer to Specifications for correct pressure values. If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve. Air Inlet and Exhaust System
Clean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual.
Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Testing and Adjusting, "Air Inlet and Exhaust System". Accessory Equipment
Check all accessory equipment for problems that may create excessive load on the engine. Repair any damaged components or replace any damaged components.