1997 Johnson Evinrude "EU" 90 thru 115 90 CV Service Manual, P/N 507267, Page 100Get this manual
Principles of Operation Flywheel
The flywheel contains the permanent magnets necessary to energize the sensor and charge coilsOnce the flywheel exceeds minimum cranking RPM, the flywheel's magnetic lines of force passing through the sensor and charge coil windings produce voltage in those circuits
When the flywheel is in good condition and correctly located, it controls ignition timing and charge coil output The sensor magnets are in ring around the flywheel hub and the charge coil magnets are in the flywheel rim Charge Coil