2004 SR Johnson 2 Stroke 9.9, 15, 25, 30 HP Outboards Service Manual, Page 115Get this manual
IGNITION COMPONENTS
COMPONENTS
Flywheel
The flywheel contains permanent magnets which energize the charge coil, sensor coil, and alternator statorOnce the flywheel exceeds minimum cranking RPM, the flywheel's magnetic lines of force pass through the ignition plate components to produce voltage in those circuits
Sensor Coil
The sensor coil contains many windings of wire wrapped around metal laminationOnce the flywheel exceeds minimum cranking RPM, the flywheel's magnetic lines of force cutting through the sensor coil windings produce approximately VSensor coil
Permanent magnets