2004 SR Johnson 2-stroke 40, 50HP Service Manual, Page 63Get this manual
MAINTENANCE ANTI-CORROSION PROTECTION
ANTI-CORROSION PROTECTION
Sacrificial Anodes
Galvanic corrosion occurs in fresh or salt waterSalt, brackish, and polluted water can accelerate corrosion"Sacrificial" anodes are intended to protect the underwater metal components of the outboard from galvanic corrosion To increase the duration of the anode protection, the starboard stern bracket (on some models) is drilled to hold an additional anodeVisually inspect anodes and metal components below water levelErosion of anodes is normal and indicates the anodes are functioning properly
The multi meter should indicate little or no resistanceIf resistance is high, check the following: Remove the anode and clean the area where the anode is installed Clean the mounting screws Install the anode and do the test again
Metallic Component Protection