62686 Mercruiser RING, PRESSURE - CLUTCH SPRING

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
Illustration 1 g06254717
(1) Valve cover
(2) Bolt and washer
(3) Seal
Remove bolts (2). Remove valve cover (1). Inspect seal (3). If the seal appears to be worn or damaged, install a new seal.
Pulling on the wiring harness may break the wires. Do not pull on the wiring harness.
Illustration 2 g06254410
(1) Wiring harness connection
(2) Transformer
(3) Extension
(4) Spark plug
Disconnect wiring harness from transformer (2). Pull transformer and extension straight away from the cylinder head.
Inspect lip seal . If the seal is worn or damaged, discard the seal and use a new seal for assembly.
Illustration 3 g00787371
(8) O-ring seal
Inspect O-ring seal (8). 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. If this condition is found, clean the surface of the seal groove. Replace seal.
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 177.8 mm (7/8 inch), 4C-4601 Spark Plug Socket, an extension, and a breaker bar to loosen spark plug (7). After the spark plug has been loosened, use the socket and extension to remove the spark plug by hand to detect problems with the threads. After the spark plug has been removed, discard the used spark plug gasket.Installing the Spark Plug
Note: Use the 9U-7516 Spark Plug Gauge to measure the electrode gap. Do not use a flat feeler gauge for measuring the electrode gap of used spark plugs. A feeler gauge will incorrectly measure the actual electrode gap because the used precious metal tips are curved.
Before installing the spark plug, set the electrode gap according to the engine Specifications manual.Adjust the electrode gap, if necessary. Bend the ground strap at the existing bend. Then bend the strap near the weld to achieve proper alignment and even spacing between the two precious metal surfaces. Measure the electrode gap after the alignment. Correct the electrode gap, if necessary.Note: Do not use anti-seize compound on spark plugs. Most of the heat is transferred through the threads and the seat area of the spark plug. Contact of the metal surfaces must be maintained to provide the heat transfer that is required.
Ensure that the spark plug is clean and free of dirt and oil.
Always use a new gasket when a spark plug is installed. If a used spark plug is installed, place a new 9Y-6792 Spark Plug Gasket on the spark plug. Orient the tabs of the gasket toward the spark plug electrode gap. Otherwise, the gasket may not seat properly. If a gasket for a spark plug is installed incorrectly, do not increase the torque on the spark plug to improve the seal. Do not reuse the gasket. Install a new gasket.
Do not overtighten the spark plug. The shell can be cracked and the gasket can be deformed. The metal can deform and the gasket can be damaged. The shell can be stretched. This will loosen the seal that is between the shell and the insulator, allowing combustion pressure to blow past the seal. Serious damage to the engine can occur.Use the proper torque.
Install the spark plug by hand until the spark plug bottoms out. Tighten the spark plug to 68 4 N m (50 3 lb ft). For more information, refer to the applicable Specifications manual.
Ensure that the transformer and the extension are clean and free from dirt and oil. Lubricate O-ring seal with one of the following lubricants:
4C-9504 Dielectric Grease
5N-5561 Silicone Lubricant
8T-9020 Dielectric Grease
Observe the lip seal as you install the transformer. Verify that the lip seal does not move out of the groove. Orient the transformer toward the wiring harness. Carefully align the socket of the transformer with the wiring harness connector. Connect the wiring harness.
Install the valve cover assembly. Refer to the applicable Specifications manual for the torque specifications.