1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 24Get this manual
IGNITION COIL TEST IMPORTANT: Ohmmeter tests can only detect certain faults in the ignition coilReplace ignition coil, if ohmmeter readings (listed in chart, following) are not as specifiedIf coil tests OK, and coil is still suspected of being faulty, use Multi-Meter DVA Tester (91-99750) or voltmeter (capable of measuring 400 volts DC, or higher) and Direct Voltage Adaptor (91-89045) to thoroughly check coil1Disconnect wires from coil terminals2Pull spark plug lead out of coil tower3Use an ohmmeter and perform the following testsTest Leads Between (+) and () Coil Terminals Between Coil Tower and () Coil Terminal Resistance Scale Reading (OHMS) (x) .02-.04 800-1100 .02-.04 (R 1) 8-11 (R 100)
Test Leads Between Brown Trigger Lead and Black Trigger Lead Between White Trigger Lead and Violet Trigger Lead
Resistance (OHMS) 700-1000 700-1000