Spark Plug: Testing and Inspection

Spark Plug Inspection:

1. Inspect the Electrodes and Ceramic Insulator for:
^ Worn or deformed Electrodes.
Improper Gap.
Oil Fouling.
Carbon Deposits.
Cracked Center Electrode Insulator.
^ Damaged Gasket.
^ Cracked Insulator.

Burned or worn Electrodes may be caused by:
^ Advanced Ignition Timing.
^ Loose Spark Plug.
^ Plug heat range too low.
^ Insufficient cooling.

Fouled Plug may be caused by:
^ Retarded Ignition Timing.
^ Oil in Combustion Chamber.
^ Incorrect Spark Plug gap.
^ Plug heat range too high.
^ Excessive idling/low speed running.
^ Clogged Air Cleaner Element.
^ Deteriorated Ignition Coil or Ignition Wires.

Electrode Gap:

2. Check the Electrode gap. Adjust the gap with a suitable Gapping Tool.

Electrode Gap: 1.1 mm (0.043 in)





Replace the Plug if the Center Electrode is rounded as shown.

Example Of Worn Plug:

3. Apply a small quantity of anti-seize compound to the Plug Threads, and screw the Plugs into the Cylinder Head finger-tight. Then torque them to 18 Nm (13 ft lb).