Spark Plug: Testing and Inspection

Spark Plug Inspection:

1. Inspect the electrodes and ceramic insulator for:
Burned or worn electrodes may be caused by:
- Advanced ignition timing
- Loose spark plug
- Plug heat range too hot
- Insufficient cooling

Fouled plug may be caused by:
- Retarded ignition timing
- Oil in combustion chamber
- Incorrect spark plug gap
- Plug heat range too cold
- Excessive idling/low speed running
- Clogged air cleaner element
- Deteriorated ignition coil
2. Replace the plug if it is fouled or worn. Do not use spark plugs other than those listed below.

Spark Plug:
PFR6L-11 (NGK)
PK20PR-L11 (DENSO)

3. Make sure that the 1.3 mm (0.051 in) plug gauge does not go into the gap for the platinum tip plug. If the gauge goes into the gap, do not attempt to adjust the side electrode; replace the plug with a new one.

Spark Plug Inspection:

Electrode Gap

4. Apply a small quantity of anti-seize compound to the plug threads before installing each plug. Screw the plugs into the cylinder head finger-tight, then torque them to 18 N.m (1.8 kgf.m, 13 lbf.ft).