1998 Johnson Evinrude "EC" 40 thru 55 2-Cylinder Service Manual, P/N 520206, Page 285Get this manual
Rectifier Ohmmeter Tests4-Amp Models
INote Disconnect battery cables before proceeding with this checkIT] IT]
1Disconnect all rectifier leads from the terminal board2Calibrate ohmmeter on appropriate scaleConnect one lead to clean engine groundConnect the other lead tothe 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 indicate the diode is damaged
OJ 3Repeat Step using the rectifier yellow lead Results should be similar