1995 Johnson/Evinrude Outboards 50 thru 70 3-cylinder Service Manual, Page 121Get this manual
Blocking DiodeElectric Models If the S.L.OWwarning system is activated when warning horn receives no oil, low oil, or fuel vacuum signal, test engine harness blocking diode1Disconnect engine harness red connector2Disconnect temperature switch tan lead3Calibrate ohmmeter on appropriate scaleConnect between tan lead and engine harness tan pin Note reading 4Reverse meter connections or press "polarity" buttonNote reading high reading in one direction and low reading in the other direction indicates the diode is good5Replace engine harness blocking diode if your test results vary6Complete all circuits disconnected during this testDR2344