C8.7 and C12.9 Marine Engines Caterpillar

Engine Vibration Is Excessive

Usage:

C8.7 CS7

Probable Causes

Inspect the vibration damper.
Engine supports
Driven equipment
Engine misfiring
Running rough

Recommended Actions

Show/hide table

Table 1
Troubleshooting Test Steps	Values	Results
1. Inspect the Vibration Damper A. Clean any debris from around the damper. Check the vibration damper for damage. B. Inspect the mounting bolts for damage and/or for wear. Refer to the Disassembly and Assembly manual.	Damper	Result: The vibration damper or the mounting bolts are damaged. Replace the damaged vibration damper or the damaged mounting bolts. Result: The vibration damper or the mounting bolts are not damaged. Proceed to Test Step 2.
2. Engine Supports A. Inspect the mounts and the brackets while you run the engine through the speed range. Look for mounts and brackets that are loose and/or broken. B. Check the alignment of the following before operating the engine under load for any length of time: 1. Mounts 2. Coupling	Engine Supports	Result: The mounts and brackets are loose and/or broken. Replace the mounts and brackets that are loose and/or broken. Result: The mounts and brackets are not loose and/or broken. Proceed to Test Step 3.
3. Driven Equipment A. Inspect the mounting bolts for the driven equipment. Inspect the alignment and the balance of the driven equipment. B. Inspect the coupling.	Driven equipment	Result: The driven equipment and the alignment are OK. Refer to Troubleshooting, "Engine Misfires, Runs Rough, or Is Unstable", for more troubleshooting information. Result The driven equipment and the alignment are not OK. Repair or replace the driven equipment.

Complete the procedure in the order in which the steps are listed.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).