1998 Johnson Evinrude "EC" 2 thru 8 Service Manual, P/N 520202, Page 39Get 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 increaseINotellf any anode has been reduced to 213 its original size (113 eroded), it must be replaced!
ITJ rn 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