1990 Johnson Evinrude "ES" 40 thru 55, P/N 507872, Page 38Get this manual
AnodesTesting and Replace ment Erosion or disintegration in salt or brackish water indicates the anodes are performing their functionThe anodes should be inspected andor replaced at intervals or corrosion of the engine will increaseINotellf any anode has been reduced to two-thirds its original size (one-third eroded), it must be replaced! To increase the duration of the anodic protection, the starboard stern bracket (on some models) is drilled to accept an additional anode
rv rt Test forohms scale Connectof one anodeSet an ohmmeter proper installation the to low lead of the ohmmeter to