Spark Plug: Testing and Inspection
Inspection1. Remove the Spark Plug.
2. Connect the Spark Plug to a high-tension lead.
3. Hold the high-tension lead with insulated pliers 5-10mm (0.20-0.39 in) from a ground.
4. Crank the engine and verify that there is a strong blue spark.
5. If there is no spark, replace the Spark Plug or high-tension lead as necessary.
6. Check the following points. If a problem is found, replace the Spark Plug.
- Damaged insulation.
- Worn electrodes.
- Carbon deposits.
- Damaged gasket.
- Burn damage.
7. Check the plug gap.
Standard: 1.0-1.1 mm (0.040-0.043 in)
Maximum: 1.3 mm (0.051 in)
8. If the plug gap is almost to or beyond the limit, replace the spark plug.
NOTE: The electrode is platinum coated. The following can scratch its platinum coating and impair its performance.
- Adjusting the plug gap.
- Using a wire brush to clean the electrode.
- Using a plug cleaner for more than twenty (20) seconds, or at more than 590 kPa (85 psi).