407920-2340 ZEXEL 0 281 020 013 BOSCH CONTROL UNIT 0281020013 4079202340

Engine Mounts
Inspect
Inspect the engine mounts for deterioration and proper bolt torque. Engine vibration may be caused by improper engine mounting and/or engine mount deterioration. Any engine mount showing deterioration should be replaced. Refer to the Torque Specifications section of this publication for recommended bolt torque values. See the Marine Engine Application and Installation Guide for more information.Crankshaft Vibration Damper
Inspect
Damage to, or failure of, the crankshaft vibration damper will increase torsional vibrations and result in damage to the crankshaft and other engine components. A deteriorating damper will cause excessive gear train noise at variable points in the speed range.The damper is mounted to the crankshaft, located behind the belt guard on the front of the engine.Removal and Installation
Refer to the Service Manual for the damper removal procedure and for the damper installation procedure.Visconic Damper
The visconic damper has a weight, located inside a fluid filled case. The weight moves in the case to limit torsional vibration. Inspect the damper for evidence of dents, cracks or leaks of the fluid.Replace the damper if the damper is dented, cracked, or leaking. Refer to the Service Manual or contact your Caterpillar dealer for damper replacement.Valve Lash
Check/Adjust
Initial valve lash adjustment on new, rebuilt or remanufactured engines is recommended at the first scheduled oil change interval due to initial wear and seating of valve train components.Subsequent adjustments should be made at Every 3000 Hour interval.This maintenance is recommended by Caterpillar as part of a lubrication and preventive maintenance schedule to provide maximum engine life.
Only qualified service personnel should perform this maintenance. Refer to the Service Manual or your Caterpillar dealer for the complete valve lash adjustment procedure.
Be sure the engine cannot be started while this maintenance is being performed. To prevent possible injury, do not use the starting motor to turn the flywheel.Hot engine components can cause burns. Allow additional time for the engine to cool before measuring/adjusting valve lash clearance.
Operation of Caterpillar engines with improper valve adjustments will reduce engine efficiency. This reduced efficiency could result in excessive fuel usage and/or shortened engine component life.
Valve Rotators
When inspecting the valve rotators, protective glasses or face shield and protective clothing must be worn, to prevent being burned by hot oil or spray.
A valve rotator which does not operate properly will accelerate valve face wear and valve seat wear and shorten valve life. If a damaged rotator is not replaced, valve face guttering could result and cause pieces of the valve to fall into the cylinder. This can cause piston and cylinder head damage.
After setting the valve lash and before installing the valve covers:1. Start the engine. Follow the engine starting procedure in this manual. Operate the engine at low idle.2. Observe the top surface of each valve rotator. Each valve rotator should turn slightly each time the valve closes.If a valve fails to rotate, contact your Caterpillar dealer.Fuel Ratio Control, Set Point, and Low Idle
Check/Adjust
The fuel ratio control limits the amount of fuel to the cylinders during acceleration. This affects the amount of exhaust smoke. The