Ignition System

Spark Plug Inspection


  1. Inspect the electrodes and ceramic insulator.

Burned or worn electrodes may be caused by:

  • Advanced ignition timing
  • Loose spark plug
  • Plug heat range too hot
  • Insufficient cooling

Fouled plug may be caused by:

  • Retarded ignition timing
  • Oil in combustion chamber
  • Incorrect spark plug gap
  • Plug heat range too cold
  • Excessive idling/low speed running
  • Clogged air cleaner element
  • Deteriorated ignition coils

  1. Worn or deformed electrodes
  2. Damaged gasket
  3. Cranked Insulator
  4. Improper gap


    Carbon deposits

    Cranked centre electrode insulator

  1. Do not adjust the gap of platinum tip plugs (A); replace the spark plug if the gap is out of specification.

Electrode Gap:

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

Service Limit:1.3 mm (0.05 in.)

  1. Replace the plug at the specified interval, or if the centre electrode is rounded (A). Use only the spark plugs listed below.

Spark Plugs:

Engine Type Spark Plug Type
D17A2, D17A8, D17A9 ZFR6J-11 (NGK)

ZFR7J-11 (NGK)


D17A5 BKR6E-N-11 (NGK)

BKR7E-N-11 (NGK)


  1. Apply a small quantity of anti-seize compound to the plug threads and screw the plugs into the cylinder head finger-tight. Then torque them to 18 Nm (1.8 kgf/m, 13 lbf/ft).