1994 Johnson/Evinrude Outboards 40 thru 55 Service Manual, Page 291Get this manual
Rectifier Ohmmeter TestsAmp Models r=lN Disconnect battery cables before proceeding with this
rv 2Calibrate ohmmeter on appropriate scaleConnect tolead one to clean engine groundConnect the other lead the
rectifier yellowgray leadNote the reading Reverse 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 damaged
[TI 1Disconnect all rectifier leads from the terminal board
[I] 3Repeat Step using the rectifier yellow lead Results should be similar