Mercury 4.2 Diesel

Section 4 - Maintenance
Page 70 90-8M0113987 eng DECEMBER 2015
4. Remove the anode assembly (anode plug and the sacrificial anode) from the top of the aftercooler end cover.
a - Aftercooler end cover
b - Anode assembly
5.
On 4.2 models, remove the anode assembly (anode plug and the sacrificial anode) from the aft end of the fluid cooler.
4.2
a - Anode assembly
b - Fluid cooler
Cleaning and Inspection
Inspection and replacement interval will vary according to the condition of the seawater and the mode of engine operation.
NOTE: Using sandpaper, fiber brush, or cleaning pad, remove the deposits from the surface of the anode before trying to
determine the amount of erosion. Do not use a mild steel brush, which might leave deposits that could accelerate corrosion.
1. Remove the deposits.
2. Inspect and measure the anode. Compare the measurements to the specifications for a new sacrificial anode and replace
the anode assembly when deteriorated 50%.
NOTE: Sacrificial anodes are available only as an assembly. Replace both the plug and anode as a unit.
Anode assembly
a - Anode plug
b - Sacrificial anode
c - Length
d - Diameter
e - Sealing washer
a
b
23266
a
23710
b
19226
a
b
c
d
e