Spark Plug Inspection And Replacement - Mercury 225 Pro XS User Manual

Spark Plug Inspection and Replacement

Avoid serious injury or death from fire or explosion caused by damaged
spark plug boots. Damaged spark plug boots can emit sparks. Sparks
can ignite fuel vapors under the engine cowl. To avoid damaging spark
plug boots, do not use any sharp object or metal tool such as pliers,
screwdriver, etc. to remove spark plug boots.
1. Remove the spark plug leads. Twist the rubber boots slightly and pull
off.
2. Remove the spark plugs to inspect. Replace spark plug if electrode is
worn or the insulator is rough, cracked, broken, or blistered, or if the
precious metal is not visible on the plug's electrode.
IMPORTANT: The color of the plug may not accurately reflect its
condition. To accurately diagnose a faulty plug, inspect the precious metal
on the plug's electrode. If no precious metal is visible, replace the plug.
a - Precious metal
MAINTENANCE
WARNING
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