2000 Johnson/Evinrude SS 25, 35 3-Cylinder outboards Service Manual, Page 34Get this manual
AnodesTesting and Replacement Erosion or disintegration in salt or brackish water indicates the anodes are performing their functionThe anodes should be inspected at intervals and replaced when necessary, or corrosion of the engine will increaseI Note If any anode has been reduced to 23 its original size (113
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
Test for proper installation of the anodeCalibrate an ohmmeter on high ohms scaleConnect one meter lead to powerhead ground and the other lead to the anodeBe sure the surface of the anode is clean to make good contactThe ohmmeter should show low readingIf not, remove the anode and clean the area where the anode is installedThe mounting screws and the anode itself should also be cleanedInstall and retest