Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 54Get this manual
Ignition Description The ignition system uses CO (Capacitor Discharge Ignition)This system provides quick voltage buildup and strong spark required for high power and high performance enginesThe COl ignition system does not incorporate mechanically operated points, therefor making this COl unit vi rtually maintenance freeAs the flywheel rotates, electrical power (alternating current) is produced by the capacitor charging coil
Ignition Component Description
Electronic Control Module (ECM)
This power is rectified by diodes so that direct current
voltage is utilized by the ignition system When the ignition driver is off, the D.Cvoltage is stored by the capacitorOnce capacitor voltage is charged to its
potential, gate signal is applied on the seR and the
residual current is dissipated through the capacitor charging coils