1994 Johnson/Evinrude "ER" 2 thru 8 outboards Service Manual, Page 256Get this manual
Rectifier Ohmmeter Tests Disconnect battery cables before proceeding with this check1Disconnect all rectifier leads from terminal boardf412Calibrate ohmmeter on appropriate scaleConnect one lead to clean engine groundConnect the other lead to the rectifier yellowgray leadNote the readingReverse the ohmmeter connections or press the "reverse polarity" button and note the reading high reading in one direction and low reading in the other direction indicates the diode is OK Two high readings or two low readings indicates the diode is damaged3Repeat Step using the rectifier yellow lead Results should be similarRepeat Step using the rectifier yellowblue lead Results should be similar1sl5Move ohmmeter lead from engine ground to rectifier red EJlead1sl6Repeat Step with ohmmeter leads connected to rectifier EJ red and yellowgray leads high reading in one direction and low reading in the other direction indicates the diode is OK: Two high readings or two low readings indicates the diode is damaged7Repeat Step using rectifier red and yellow leads Results should be similar8Repeat Step using rectifier red and yellowblue leads Results should be similar