Spark Plug Inspection And Replacement; Corrosion Control Anode - Mercury FourStroke 2.5 Service Manual

Maintenance

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 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

Corrosion Control Anode

Your outboard has a corrosion control anode installed on the gearcase. An anode helps protect the outboard against galvanic
corrosion by sacrificing its metal to be slowly corroded instead of the outboard metals.
Page 1B-6
WARNING
!
26899
26946
26947
0.9 mm (0.035 in.)
Nm lb‑in.
27
90-8M0065421 NOVEMBER 2012
lb‑ft
20