1978 Johnson 55 HP Outboards Service Manual, Page 101Get this manual
KEY SWITCH CHECK
(With continuity light or ohmmeter)
1Disconnect battery leads
2With key switch in "OFF" position, connect continuity light or meter leads between key switch "BATT" and "A" terminalsLight or meter should not show continuityOFF
3Turn key switch to "ON" position
Light or
meter should show continuityON
key switch to "START" positionLight or meter should still show continuitySTART
5With key held in "START" position, transfer lead from "A" terminal to "s" terminalLight or meter should still show continuitySTART