1. Check the spark plugs as follows and adjust or replace if necessary:
- Check spark gaps
- Check electrode contamination
- Check for soot
- Check for cracks in the center electrode insulator.
2. If the electrodes are badly burned, the following reasons can be assumed:
- Spark plugs run on a lean air-fuel mixture
- Too large ignition timing
- Low glow number of spark plugs
- Cooling system failure
- Insufficient tightening of candles
3. If the spark plugs are completely black from soot, the following reasons can be assumed:
- Long-term operation at idle speed
- Spark plugs were running on a too rich air-fuel mixture
- Late ignition
- Faulty ignition coil, faulty noise suppression capacitor or high voltage wires
- Worn piston rings and valve guides
- Abnormal spark gap
- Too high glow number of candles
4. If there is carbon deposits on the electrodes, clean with a sandblaster.
Attention. Completely remove sand after sandblasting.
5. If the center electrode is spherical, replace the spark plug.
Use spark plugs conforming to the ISO standard (international standard) labeled
.
Types of spark plugs
- NGK: ZFR5F11*
- DENSO: KJ16CR-L11*
*: Uses spark plugs for fuel injected engines.
The package is labeled
.
Spark clearance:
- Standard spark gap: 1.0-1.1mm
6. When installing the candle, insert it into the spark plug wrench, hand-tight until it touches the mounting location, and then tighten to the required torque.
: 18 N·m (1.8 kg m)