1978 Evinrude Outboards 9.9/15HP Service Manual, Page 31Get this manual
DESCRIPTION The magneto Capacitor Discharge (C.D Ignition System consists of five major componentsThey are: 1Flywheel into the magnets polarityAssemblyContains two magnets, cast flywheel 180 degrees apartThese are magnetically charged of opposite See Figure 4-1
aCapacitor Charge Circuit bTriggering Circuit cCapaCitor Discharge (C.D Circuit 5Ignition CoilsGenerate the very high voltage required to ignite the fuel in each cylinderCharge Coil Assemblylarge coil of wire which generates Alternating Current (A.C that is sent into the Power PackSee Figure 4-1Sensor Assemblysmall coil of wire which generates the triggering voltage for the Power PackSee Figure 4-1Power Pack Assembly (C.D.2)Contains the electronic circuits necessary to produce ignition at the proper time:
THEORY OF OPERATION
Simplified basic circuit illustrations support the theory of operation and are intended for instructional use onlyThe theory of operation and schematics for the Magneto Capacitor Discharge Ignition System use the following three basic electronic components: DIODEcomponent in which current can flow only in one direction (as indicated by the arrow)GATE SILICON CONTROLLED FIE (S.C.Rcomponent (like diode) in which current can flow through the SCRonly in one direction (as indicated by the arrow) and in which the current can flow only when the GATE of the S.C.Rreceives positive (+) input to trigger (or "turn-on"the S.C.R CAPACITORcomponent that stores voltageOne end of the capacitor is positive (+) and the other end is negative (-)The voltage is stored, until the trigger circuit is activated4