Spark Plug: Service and Repair

Spark Plug Wire Remover:

Special Service Tool (s)

REMOVAL

Spark Plug Wire Remover:

1. Use the special tool with a twisting motion to pull the spark plug wire off the spark plugs.

CAUTION
^ Spark plug wires must be connected to the proper ignition coil terminal. Mark spark plug wire locations before removing them.
^ It is important to twist the spark plug wire boots while pulling upward to avoid damage to the spark plug wire.

2. Remove the spark plug.

NOTE
^ Use compressed air to remove any foreign materials from the spark plug well before removing the spark plugs.
^ If an original spark plug is reused, make sure it is placed in the same cylinder from which it was taken. New spark plugs can be used in any cylinder.







3. Inspect the spark plugs for a bridged gap.
^ Check for deposit buildup closing the gap between the electrodes. Deposits are caused by oil or carbon fouling.
^ Clean the spark plug.







4. Check for oil fouling.
^ Check for wet, black deposits on the insulator shell bore electrodes, caused by excessive oil entering the combustion chamber through worn rings and pistons, excessive valve-to-guide clearance or worn or loose bearings.
^ Correct the oil leak concern.
^ Install a new spark plug.







5. Inspect for carbon fouling. Look for black, dry, fluffy carbon deposits on insulator tips, exposed shell surfaces and electrodes., caused by a spark plug with an incorrect heat range, dirty air cleaner, too rich a fuel mixture or excessive idling.
^ Clean the spark plug.







6. Inspect for normal burning.
^ Check for light tan or gray deposits on the firing tip.







7. Inspect for pre-ignition, identified by melted electrodes and a possibly damaged insulator. Metallic deposits on the insulator indicate engine damage. This may be caused by incorrect ignition timing, wrong type of fuel or the installation of a heli-coil insert in place of the spark plug threads.
^ Install a new spark plug.







8. Inspect for overheating, identified by white or light gray-brown spots and with bluish-burnt appearance of electrodes. This is caused by engine overheating, wrong type of fuel, loose spark plugs, spark plugs with an incorrect heat range, low fuel pump pressure or incorrect ignition timing.
^ Install a new spark plug.







9. Inspect for fused deposits, identified by melted or spotty deposits resembling bubbles or blisters. These are caused by sudden acceleration.
^ Clean the spark plug.







10. Adjust the spark plug gap as necessary.

INSTALLATION







1. To install, reverse the removal procedure.