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.





2. Check the electrode gap. Adjust the gap with a suitable gapping tool.

Standard Electrode Gap: 1.1 /+0 -0.1/ mm (0.043 /+0 -0.004/ in)

Example Of Worn Plug:

3. Replace the Plug if it is fouled or worn.


NOTE: Spark Plugs; ZFR5F-11 (NGK), KJ16CR-L11 (Nippondenso)

4. 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 N.m (1.8 kgf-m, 13 lbf-ft).