Spark Plug Inspection

1. Check the following items to see that electrodes are not burnt, and insulators are not broken, and how the porcelain insulator is burnt.

- Broken insulators
- Wearing electrodes
- Deposited carbon

For cleaning, use a plug cleaner or wire brush. Clean porcelain insulator above shell as well.

- Damaged or broken gasket.
- Burnt condition of porcelain insulator at spark gap.

Dark deposit of carbon indicates too rich a fuel mixture or extremely low air intake. Also, misfiring due to excessive spark gap is suspected.

White burn indicates too lean a fuel mixture or excessively advanced ignition timing. Also insufficient plug tightening is suspected.

2. Clean with a plug cleaner. Use an air gun to remove dust deposited on plug threads.

Spark Plug Inspection: Step (3):

3. Check plug gap using a plug gap gauge and adjust if it is not as specified.

Standard value: 1.0 - 1.1 mm (0.039 - 0.043 in.)