0314891 JOHNSON THROTTLE VALVE

Engine Valve Lash
Initial Valve Lash Adjustment.
Initial valve lash adjustment 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 the Every 2000 Hour interval.Check/Adjust
This maintenance is recommended by Caterpillar as part of 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.Measure the valve lash with the engine stopped. To obtain an accurate measurement, allow at least 20 minutes for the valves to cool to engine cylinder head and block temperature.
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.
If a damaged rotator is not replaced, valve face guttering could result in pieces of the valve to fall into the cylinder. This can cause piston and cylinder head damage.
Refer to the Service Manual for the valve rotator inspection procedure.Fuel Injection Nozzles
Test/Exchange
Fuel injection nozzles are subject of tip wear. Tip wear, a result of fuel contamination, can cause:* increased fuel consumption.* black smoke.* misfire.* rough running.Nozzles should be cleaned, inspected, tested, and replaced if necessary. Refer to Special Instruction SEHS7292, for using the 8S-2245 Nozzle Cleaning Kit. Consult with your Caterpillar dealer about nozzle cleaning and testing.
Never wire brush or scrape a nozzle. Wire brushing or scraping a nozzle will damage the finely machined orifice. Proper tools for cleaning and testing nozzles can be obtained from authorized Caterpillar dealers.
Abnormal engine running, smoke emission, and engine knock can be symptoms of nozzle malfunction. Each nozzle must be isolated one at a time in order to determine the malfunctioning nozzle.1. Start the engine.
A nozzle will be damaged if the top of the nozzle turns in the body. The engine will be damaged if a defective nozzle is used because the fuel spray pattern that comes out of the nozzle will be incorrect. Nozzles can be permanently damaged by twisting if only one wrench is used to loosen or tighten the fuel line nuts. Do NOT let the tops of the nozzles turn when the fuel lines are loosened. Use one wrench to hold the nozzle and another to loosen the fuel line nut.
2. Loosen each fuel line nut at the fuel injection pump, one at a time. A cloth or similar material must be used to prevent fuel from spraying on the hot exhaust components. Tighten each nut before loosening the next nut.3. A defective nozzle may be identified when a fuel line nut is loosened and:* the exhaust smoking is partially or completely eliminated.* irregular running is not affected.A nozzle suspected of being defective should be removed. A new nozzle should be installed in the cylinder to determine if the removed nozzle is defective.Removing and Installing Fuel Injection Nozzles
Special tooling is required to remove and install nozzles. Refer to the Service Manual for information. Consult with your Caterpillar dealer for assistance.Turbocharger
Periodic inspection and cleaning is recommended for the turbocharger compressor housing (inlet side) and the aftercooler core. Since the crankcase fumes are ingested through the inlet air system, oil and combustion by-products may collect in these two areas.This buildup, over time, can contribute to loss of engine power, increased black smoke, and overall loss of engine efficiency. This buildup is only a possible contributor to these conditions.Operating the engine until the turbocharger fails can severely damage the turbocharger's compressor wheel and/or the engine. Damage to the turbocharger compressor wheel could allow parts from the compressor wheel to enter the engine cylinder, causing additional damage to the piston, valve, and cylinder head.
Turbocharger bearing failures can cause large quantities of oil to enter the air intake and exhaust systems. Loss of engine lubricant can result in serious engine damage.Minor leakage of a turbocharger housing under extended low idle operation will not cause problems as long as a turbocharger bearing failure has NOT occurred.When a turbocharger bearing failure is accompanied by a significant engine performance loss (exhaust smoke or engine speed up at no load), DO NOT continue engine operation until the turbocharger is repaired or replaced.
An inspection/check of your turbocharger will minimize unscheduled downtime and reduce the chance for potential damage to other engine parts. Turbocharger components require precision clearances and balancing due to operation at high rotational (torsional) speeds. Severe Service Applications can accelerate component wear and may suggest the need to Inspect/Repair/Replace the cartridge at reduced intervals to ensure maximum reliability and retention of the full core.Removal and Installation
For removal and installation, or repair/replacement options of turbochargers, see your Caterpillar dealer. Refer to the Service Manual for this engine or consult your Caterpillar dealer for the procedure and specifications.