Spark Plug: Testing and Inspection

Spark Plug Inspection
1. Inspect the electrodes and ceramic insulator for:
- Improper gap
- Oil-fouling
- Carbon deposits
- Cracked center electrode insulator

Burned or worn electrodes may be caused by:
- Lean fuel mixture
- Advanced ignition timing
- Loose spark plug
- Plug heat range too high
- Insufficient cooling

Fouled plug may be caused by:
- Rich fuel mixture
- Retarded ignition timing
- Oil in combustion chamber
- Incorrect spark plug gap
- Plug heat range too low
- Excessive idling/low speed running
- Clogged air cleaner element
- Deteriorated ignition coil or ignition wires





2. Clean the electrodes with a spark plug cleaning machine, or with a wire brush. Clean between the outer shell and center insulator with a stiff wire as shown. Clean plug threads with a wire brush.





3. Replace the plug if the center electrode is rounded as shown.

Spark Plug:
BCPR6E-11 (NGK), Q2OPR-U11 (ND)
BCPR6EY-11 (NGK), BCPR6EY-N11 (NGK)
(for all normal driving)
BCPR7E-11 (NGK), Q22PR-U11 (ND)
BCPR7EY-11 (NGK), BCPR7EY-N11 (NGK)
(for hot climates or continuous high speed driving)
BCPR5E-11 (NGK), Q16PR-U11 (ND)
BCPR5EY-11 (NGK), BCPR5EY-N1 1 (NGK)
(for cold climates)

4. Adjust the gap with a suitable gapping tool.

Electrode Gap: 1.0 - 1.1 mm (0.039 - 0.043 in)

5. Screw the plugs into the cylinder head finger tight, then torque them to 22 N-m (2.2 kg-m, 16 lb-ft).

NOTE: Apply a small quantity of anti-seize cormpound to the plug threads before installing.