Spark Plug inspection

Inspect the electrodes and ceramic insulator for:

Fig 1: Identifying Spark Plug Component Location

Burned or worn electrodes may be caused by:
- Advanced ignition timing
- Loose spark plug
- Plug heat range too hot
- Insufficient cooling
Fouled plugs 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 or ignition wires
Check the electrode gap.
- Adjust the gap with a suitable gapping tool.
  Electrode Gap
  ELECTRODE GAP STANDARD SPECIFICATION
  
  Standard 1.1 - ₁ mm (0.043- ₀₀₄ in)
  
  Fig 2: Identifying Electrode Gap
- Replace the plug if the center electrode is rounded as shown below:
  
  Fig 3: Identifying Rounded Electrode
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).