GEAR ASSEM. (12 TEETH) 9M0888 - Caterpillar

Ignition systems can cause electrical shocks. Avoid contacting the ignition system components and wiring.Do not attempt to remove the valve covers when the engine is operating. The transformers are grounded to the valve covers. Personal injury or death may result and the ignition system will be damaged if the valve covers are removed during engine operation. The engine will not operate without the valve covers.
Maintenance of the spark plugs is required to achieve the following benefits:
Normal fuel consumption
Normal level of emissions
Maximum service life of the spark plugsThe service life of the spark plugs is affected by fouling due to deposits from the oil and by peak voltage. Maintenance of the ignition system is also affected by voltage. Higher voltage is required by higher inlet manifold air pressure and a higher compression ratio. Higher voltage reduces the service life of components such as spark plugs, wires, and transformers.Removing the Spark Plug
Remove the valve cover. Refer to the Disassembly and Assembly Manual, "Valve Covers" for the removal procedure.
Remove the spark plug. Refer to the Disassembly and Assembly Manual, "Spark Plugs - Remove and Install" for the removal procedure
Personal injury can result from air pressure.Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing.The maximum air pressure for cleaning purposes must be reduced to 205 kPa (30 psi) when the air nozzle is deadheaded.
Debris may have collected in the spark plug well. Thoroughly remove any debris. Use compressed air. The maximum air pressure for cleaning purposes must be below 205 kPa (30 psi). Ensure that the area around the spark plug is clean and free of dirt and debris.Inspecting the Spark Plug
Inspect the spark plug closely for damage. The condition of the spark plug can indicate the operating condition of the engine.
Illustration 1 g06055360
(1) Spark plug
(2) TransformerThe terminal post must not move. If the terminal post can be moved by hand, carefully tighten the post into the threads of the insulator. If the post cannot be tightened, discard the spark plug.Inspect the insulator for cracks. If a crack is found, discard the spark plug.Excessive buildup of oil in the spark plug well is an indication of a damaged lip seal on the transformer. If this condition is found, clean the surface of the seal groove.Inspect the shell for damage. Cracks can be caused by overtightening the spark plug. Overtightening can also yield the metal which loosens the shell. Discard any spark plug that has a shell that is cracked or loose.Cat spark plugs have precious metal tips on the electrode and the ground strap. This material will gradually erode. Use extreme care when you set the electrode gap. Maintain even spacing and proper alignment between the two precious metal surfaces.Replace the spark plug if the precious metal is worn off.A light brown deposit or a beige deposit around the electrode is produced by normal operation.Deposits that are gray or black may be caused by the following substances:
Excessive oil
Use of the wrong oil
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