20775507 Volvo.Penta Hex. socket screw

Recommended Actions
Batteries and/or Battery Cables
Inspect the main power switch, battery posts, and battery cables for loose connections and for corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.
Inspect the batteries.
Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".
Load test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries". Starting Motor Solenoid or Starting Circuit
Check the operation of the engine start switch. Monitor the engine start switch on Caterpillar Electronic Technician (ET). Refer to the appropriate troubleshooting test that is applicable to your engine if repairs are required.
Test the operation of the starting motor solenoid.
Check the wiring to the starting motor solenoid. Starting Motor or Flywheel Ring Gear
Test the operation of the starting motor.
Inspect the solenoid on the starter and the flywheel ring gear for damage. Prelubrication System (if applicable)
If equipped, inspect the prelubrication system for proper operation.Shutdown Switch
Use Cat ET to monitor the status of the engine. Check the status of engine shutdowns that are "ACTIVE" due to shutdown switches. Determine the cause for the engine shutdown and take the necessary action in order to resolve the shutdown.Crank Enable Switch (if applicable)
Ensure that the crank enable switch is not faulty.Transmission or Engine Accessories (if applicable)
If the engine's application has a transmission neutral switch, test the operation of the transmission neutral switch. Ensure that the machine is in neutral gear before attempting to start the engine.
Ensure free movement of the driveline.
Ensure that the timing pin was not left in the flywheel housing.
Remove any engine accessories that may lock up the engine and inspect any engine accessories that may lock up the engine. The following list illustrates examples of engine accessories that may lock up the engine:
Hydraulic pump that is driven from the rear gear group
Air compressor
Engine oil pump
Other components that are driven by the engineHydraulic Cylinder Lock
Check for fluid in the cylinders (hydraulic cylinder lock) by removing the individual unit injectors.Note: Drain the fuel from the cylinder head. Fuel will flow from the cylinder head into the cylinders when the unit injector is removed.Internal Engine Problem
Disassemble the engine. Refer to the Disassembly and Assembly manual. Inspect the internal components for the following conditions:
Seizure
Broken components
Bent componentsThe Secondary ECM is Not Connected to the −Battery
If the yellow "SECONDARY ECM READY" indicator on the panel for the MPD does not illuminate and the red "OVERSPEED" indicator illuminates upon an attempt to start the engine, perform the following procedure.
At the power distribution panel, open the 20 Amp circuit breaker for the panel for the MPD. The MPD will turn off.
Reset the air shutoffs (if equipped). Cycle the power to the ECM.
Start the engine.
At the power distribution panel, close the 20 Amp circuit breaker for the panel for the MPD. The MPD will turn on. Determine the reason for the secondary ECM to be disconnected from battery power. The secondary ECM can be connected to battery power and the engine will continue running. The yellow "SECONDARY ECM READY" indicator will illuminate on the panel for the MPD.