1993 Johnson Evinrude "ET" 40 thru 55 Service Manual, P/N 508283, Page 131Get this manual
7 DR4256
STEPIGNITION PLATE OUTPUT TEST
To prevent accidental starting of engine while testing, twist and remove both spark plug leads
1Twist and remove primary leads from ignition coils2Connect No1 ignition coil primary lead to Stevens Instrument load adapter NoPL-88 red leadConnect adapter black lead to clean engine ground If Stevens Instrument NoPL-88 is not available, you can make an adapter using 10-ohm, 10-watt resistor, Radio Shack No271 -132, or equivalent3Set peak-reading voltmeter to "POS" and "500"
Connect voltmeter red lead to adapter red lead and meter black lead to clean engine ground