Burning or wear of the electrodes can occur due to:
- early ignition
- Loose spark plug
- Too high thermal range spark plugs
- Insufficient cooling
Candle fouling can occur due to:
- late ignition
- Oil entering the combustion chamber
- Incorrect spark gap
- Spark plug heat range too low
- Long engine idling/low speed
- Clogged air filter element
- Damage to high voltage wires
2. Check the spark gap.
Adjust the spark gap with a suitable tool.
If the center electrode is rounded as shown, replace the spark plug:
3. Apply a small amount of anti-seize compound to the threads of the spark plugs and screw the spark plugs into the cylinder head by hand. Then tighten them with a torque of 18 Nm (1.8 kgf/m).
Recommended spark plugs
ZFR5J-11 (NGK)
KJ16CR-L11 (DENSO)