Other information:
Inspection and Verification
Verify the customer concern.
Visually inspect for obvious signs of mechanical or electrical damage.
If an obvious cause for an observed or reported concern is
found, correct the cause (if possible) before proceeding to the next
step
If the cause is not visually evident, verify the symptom and refer to the Symptom Chart...
Inspection
NOTE:
Dropped spark plugs should always be discarded.
Unfired
An unfired spark plug should appear very clean
with a pure nickel finish to the threads and ground strap. The center
electrode ceramic insulator surface is often a matte or dull finish and
pure white in color...