Spark Plug: Inspection
- Check the spark plug for damage. If defective, replace the spark plug.
- Check the spark plug electrode and condition of the insulator. If abnormal, check and repair the cause and replace the spark plug.CAUTION: Do not use a plug cleaner or brush to clean the spark plug as it may damage the electrode area.
- Normal:
Brown to grayish-tan deposits and slight electrode wear indicate correct spark plug heat range.
- Carbon fouled:
Dry fluffy carbon deposits on the insulator and electrode are mostly caused by slow-speed driving in town, weak ignition, too rich fuel mixture, etc.
- Oil fouled:
Wet black deposits show oil entrance into combustion chamber through worn piston rings or increased clearance between valve guides and valve stems.
- Overheating:
A white or light gray insulator with black or brown spots and bluish burnt electrodes indicate engine overheating, wrong selection of fuel, or loose spark plugs.
- Normal:
- Visually check the spark plug gap (A). If faulty such as deformation is found, replace the spark plug.
CAUTION:
Do not adjust the gap for the spark plug.