Spark Plug: Testing and Inspection

INSPECTION OF SPARK PLUGS

1. Disconnect spark plug cable from the spark plug.

NOTE: If the spark plug cable is removed by pulling on the cable, it may be damaged.

2. Using a plug wrench, remove all plugs from cylinder head.

CAUTION: Use care not to allow foreign matter to enter through plug holes.

3. Check the spark plugs for the following:
Broken insulator
Worn electrode
Carbon deposits
Damaged or broken gasket
Burnt condition of porcelain insulator at spark gap.

NOTE: Dark deposits indicate too rich a fuel mixture, light (white) deposits indicate too lean a fuel mixture, advanced ignition timing or insufficient plug tightening

4. Check plug gap using a plug gap gauge and adjust if necessary.

Standard value: .039 - 0.043 in (1.0 - 1.1 mm)

5. Tighten spark plug to specified torque. If overtorqueing occurs, damage to threaded portion of cylinder head might result.

Spark plug torque: 15-21 ft.lb (20 - 30 Nm)