GASKET FUEL RETURN ELBOW 4N9337 - Caterpillar

Note: Condensation can form in spark plugs that have precombustion chambers. Condensation can cause difficulty for cold start-ups. To avoid condensation, maintain the coolant in the cylinder block at a minimum temperature of 43 °C (110 °F) continuously.The 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, leaner air to fuel operation, a higher compression ratio, and retardation of the timing. Higher voltage reduces the service life of components such as spark plugs, wires, and transformers.The service life of the spark plug is different for different applications. The expected service life of the spark plug is approximately 3000 service hours. This service life if for an engine that is running on pipeline natural gas at standard performance sheet settings and conditions. To help predict the spark plug service life, use Cat Electronic Technician (ET) to monitor the "Cylinder #X Transformer Secondary Output Voltage Percentage" parameter. The value of this parameter will increase as the spark plug gap wears over time. Experience at the particular site will help to determine the proper interval for replacement of the spark plugs.If a diagnostic code is generated for the ignition transformer secondary circuit, replacement of the spark plug may be necessary. Misfire and a cold cylinder are other indications of a worn spark plug. Use Cat ET to monitor the exhaust port temperatures in order to locate a cold cylinder.Removing the Spark Plug
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.
Illustration 1 g00925913
(1) Cover (2) Wiring harness (3) Transformer (4) Seal (5) Spark plug (6) Valve cover
Remove cover (1).
Remove wire harness (2) from transformer (3) .
Remove the two remaining bolts that secure transformer (3). Remove transformer (3) from valve cover (6) .
Inspect O-ring seal (4). If the seal is hard, cracked, or melted, install a new seal.
Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.
Note: Excessive buildup of oil in the spark plug well is an indication of a damaged lip seal on the transformer.
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 207 kPa (30 psi). Ensure that the area around the spark plug is clean and free of dirt and debris.
Use a 216-1685 deep well socket, an extension, and a breaker bar to loosen spark plug (5). After the spark plug has been loosened, use the socket and extension to remove the spark