1991 Johnson/Evinrude EI 60 thru 70 outboards Service Manual, Page 251Get this manual
TTL Models
1Disconnect battery cables from battery2Disconnect red, purple, yellow and yellowgray rectifier leads from terminal boardr:;'] 3Calibrate ohmmeter on appropriate scaleConnect meter
black lead to rectifier yellow leadConnect meter red lead to rectifier red lead4Note meter readingReverse the ohmmeter connections or press the "Reverse Polarity" button and note the reading very high reading in one direction and low reading in the other direction indicates that the diode is OK Two high readings or two low readings indicate that the diode is damaged5Move meter red lead to rectifier purple leadRepeat Step Results should be similar6Move meter red lead to rectifier caseRepeat Step Results should be similar7Move meter black lead to rectifier yellowgray leadConnect meter red lead to rectifier red leadRepeat Steps 4, and 6Isl 8Connect meter black lead to rectifier caseTouch rectifier purple lead to case, then connect meter red lead to purple leadMeter needle should move up the scale slightly, then return to infinity (00) If meter needle does not move or if needle moves up scale and does not return, replace rectifier9If your test results vary, replace rectifier