1988 Johnson Evinrude "CC" 9.9 thru 30 Service Manual, P/N 507660, Page 151Get this manual
Step 2 Sensor Coil Running Tests Using C.DVoltmeter and Adapter
Sensor Coil Output TestSeparate the five -wire connector and plug both ends into the adapterSet the voltmeter switches to "+and "50 Turn all adapter switches ON
INote Rou.te all tester leads so they do not interfere with moving
engine parts
APlace the meter black lead in jack "B Place the meter red lead in jack "C Start the engine and run at RPM where problem existsObserve the meterStop the engineBReverse the meter leads to jacks "C" and "B Start the engine and run at RPM where problem existsObserve the meterStop the engine