1988 Johnson/Evinrude "CC" 40 thru 55 Models Service Manual, Page 151Get this manual
Running Tests Using C.DVoltmeter and AdapterAll Models The C.D adapter permits tests on the charge coil, sensor coil, and power pack while the engine is runningThe connectors are plugged into the adapter ONE PAIR AT TIME and the jacks permit tapping the voltmeter into that particular circuitWhen the adapter switches are in the ON position, the circuit is complete through the adapterIn the OFF position, the signal goes from the input side to the meter jack only, eliminating any influence from the output side of the adapterThe engine will not run with switches in OFF position