7254A 3 Mariner FRONT COVER ASSEMBLY (WITHOUT DECALS)

Recommended Actions
Data Link Communications
Check for diagnostic codes that are related to the Cat Data Link. If there is a problem with the Cat Data Link, the master Electronic Control Module (ECM) will not be able to communicate with the slave ECM. Engine cranking will be suspended. Refer to Troubleshooting, "Cat Data Link - Test" for information that is related to troubleshooting the Cat Data Link.Batteries and/or Battery Cables
Inspect the main power switch, battery posts, and battery cables for loose connections and corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.
Check that the battery cables are sized correctly for the application. Ensure that the rating for the battery cables is consistent with the cold cranking amperage for the batteries.
Inspect the batteries.
Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure". Note: The 177-2330 Battery Analyzer may also be used to check the battery condition. Refer to Tool Operating Manual, NEHS0764, "USING THE 177-2330 BATTERY ANALYZER" for operating instructions.
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 and/or Starting Circuit
Test the operation of the starting motor solenoid. If the solenoid does not operate properly, install a new solenoid.
Check the wiring to the starting motor solenoid. Starting Motor Pinion and/or Flywheel Ring Gear
If the pinion engages the flywheel but the flywheel does not turn, there may be a problem with the starting motor. If the starting motor turns but the flywheel does not turn, inspect the gear teeth, the clutch jaws, or other components of the starting motor.Inspect the pinion and the flywheel ring gear for damage. If the teeth of the pinion and/or the flywheel ring gear are worn or broken, replace the parts.If the pinion does not engage correctly with the flywheel, the pinion shaft may be stuck. Remove the pinion. Grease the splines of the drive shaft and the pinion.If the pinion does not engage the flywheel, the clutch jaws may be broken.Before you remove the starting motor, turn the crankshaft by hand. Ensure that a mechanical failure inside the engine is not preventing the crankshaft from turning. If the crankshaft will turn by hand, try the starting motor again. If the starting motor does not turn the crankshaft, remove the starting motor. Repair the starting motor or replace the starting motor.Low Air Pressure
Determine the cause of the low air pressure. Inspect the air lines for leaks. Repair any leaks in the air lines.Static Load
Confirm that the driven equipment is not preventing the crankshaft from turning. Attempt to turn the crankshaft by hand. If necessary, disengage the driven equipment and test the engine. Refer to Installation Guide, LEBW5339, "G3500 GAS ENGINES APPLICATION & INSTALLATION GUIDE " for related information.Wiring for the Starting System
Inspect the wiring for the starting system. If the faulty wiring is suspected, refer to Troubleshooting, "Starting - Test" for information that is related to troubleshooting the wiring.Internal Mechanical Problem
If the crankshaft will not turn and the driven equipment is disengaged, remove the spark plugs. Check for fluid in the cylinders. If this is not the problem, the engine must be disassembled in order to investigate internal mechanical problems. Possible internal problems include the following conditions:
Bearing seizure
Piston seizure
Valve and piston contactHarness Code Circuitry
The harness inside the terminal box for the slave ECM has a jumper wire (harness code circuit) that connects terminals J3-29 and J3-60. The ECM uses this circuit to modify the operational mode of the ECM. This will allow the ECM to operate as the slave ECM. The jumper wire must be connected in order for the engine to crank. The jumper wire must remain connected in order for the engine to run.Check the continuity between terminals J3-29 and J3-60. Verify that the jumper wire is in good condition. Perform repairs, as needed.