Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 50Get this manual
IGNITION SYSTEM
Trigger Coil
CAUTION
DO NOT rotate flywheel during test or damage to meter may result1Use an ohmmeter to perform the following test149-223
2If meter readings are other than specified, replace trigger coilRefer to "Ignition Components Removal and Installation," following