Spark Plug Inspection And Replacement - Mercury 40/50 Series Manual

Spark Plug Inspection and Replacement

Damaged spark plug boots may emit sparks which can ignite fuel
vapors under the engine cowl, resulting in serious injury or death
from a fire or explosion. To avoid damaging the spark plug boots,
do not use any sharp object or metal tool to remove the spark
plug boots.
1. Remove the spark plug boots. 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,
blistered, or fouled.
3. Set the spark plug gap (0.9–1.0 mm).
4. Before installing the spark plugs, clean off any dirt on the spark
plug seats. Install the plugs finger‑tight, and then tighten 1/4
turn or torque to specifications.
MAINTENANCE
WARNING
!
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