Spark Plug Inspection And Replacement - Mercury 2.5 FourStroke Operation, Maintenance & Installation Manual

Spark Plug Inspection and Replacement

Damaged spark plug boots may emit sparks that 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 boot. Twist the rubber boot slightly and pull off.
2. Remove the spark plug 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 to specification.
Spark Plug
Spark plug gap
4. Before installing spark plug, clean off any dirt on the spark plug seat.
Install plug finger‑tight, and then tighten 1/4 turn or torque to
specifications.
Description
Spark plug
eng
MAINTENANCE
WARNING
!
39
26899
26946
26947
0.9 mm (0.035 in.)
Nm lb‑in.
27 –
lb‑ft
20