2004 SR Johnson 2 Stroke 9.9, 15, 25, 30 HP Outboards 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 corrosionOutboards are equipped with sacrificial anodes
Testing ProcedureContinuity
Calibrate multimeter on "HIGH" ohm scaleConnect meter leads between engine ground and anode surface
1Black meter lead
2 Red meter lead
TYPICAL 1Anode
000288R