1998 Johnson Evinrude "EC" 25, 35 HP 3-Cylinder Outboards Service Manual, Page 109Get this manual
Output Tests
All cranking output tests must be performed with spark plugs installed and torqued in the cylinder headIf necessary to remove the spark plugs, be sure to keep the spark tester away from open spark plug holes
STEPTOTAL OUTPUT TEST
InTo avoid electrical shock, do not handle ignition coil or spark
tester during cranking tests1Twist and remove all spark plug leads
2Adjust the gap on the spark tester to 3B in(9 mm)Connect tester leads to the spark plug leadsSecure tester clip to clean engine ground(51 mm) from any metal surface3If equipped, install the clip onto the emergency stop switchCrank the engineSpark should jump each tester gap in sequence4Refer to Troubleshooting Sequence Chart, Page 3-21 Start with your specific fault symptom and continue troubleshooting in sequence