1975 Evinrude 2HP Model 2502 Full Factory Service Manual, Page 26Get this manual
4-2 DESCRIPTION
BREAKERIl
MAGNETO
The ignition system consists of flywheel type magneto connected to the spark plug through high tension leadThe magneto ts selfcontained electrical generating unit consisting of an armature plate with one coli and lamination assembly, condenser, and breaker assemblyA permanent magnet cast into the flywheel completes the assembly
THEORY OF OPERATION
The magneto employs the interaction of the fast moving flywheel magnet and stationary coil to generate an electric current of voltage sufficient to arc across the spark plug air gapThis creates the spark that ignites the fuel in the cylinderThe ignition coil actually consists of two coilsOne, called the primary, consists of relatively few turns of heavy gage copper wireThe
other, called the secondary, consists of many turns of fine gage wire