Mercury Mariner Outboards 2.2 / 2.5 / 3.0 Service Shop Manual, Page 22Get this manual
Secondary Ignition Coil Test IMPORTANT: Ohmmeter tests can only detect certain faults in the secondary ignition coilReplace ignition coil if ohmmeter reading listed in chart are not as specifiedIf coil tests OK, and coil is still suspected of being faulty, use magneto analyzer to thoroughly check coilFollow coil test outlined in analyzer manualMeter Range Ohm Reading
Check Primary Winding Test Connect Positive (+Ohmmeter Lead to Co il Black White Lead and Negative (-) Lead to Coil Ground Secondary Winding Test Connect Positive (+Ohmmeter Lead to Spark Plug Lead Terminal and Negative (-Lead to Coil Ground