1990 Johnson Evinrude "ES" Cross V 88 thru 115, 150 thru 175, P/N 507874, Page 101Get this manual
Sensor Coil (Timer Base and Sensor Coil Assembly)
f2l The sensor coil consists of many windings of wire wrapped 12J around metal laminationOnce the flywheel exceeds a
minimum cranking RPM, the flywheel's magnetic lines of force cutting through the sensor coil windings produce approximately voltsThis voltage is supplied to the power pack to control small electronic switches (SCR's) which, in turn, direct power pack output to the correct ignition coil primary V4The timer base has four sensor coils; one per cylinder V6The timer base has six sensor coils; one per cylinderPower PackThe power pack
has three major functions:
aThe power pack receives its operating voltage from the charge coil and converts it into direct current for storagebThe power pack stores this direct current in capacitorCThe power pack uses series of electronic switches (SCR's), activated by sensor coil output, to select the correct ignition coil primary winding for firingThe power pack has one SCR for each ignition coil it controls All ModelsThere is one power packKey Switch key switch and emergency ignition cutoff switch are connected to the power packs through the engine wiring harnessWhen activated, these switches direct the power pack output to ground, stopping the ignition systemIgnition Coil around compacted ferrite materialThe coil has primary and secondary terminal connection and ground plateThrough mutual induction, the ignition coil transforms power pack output to as much as 40,000 volts to fire the spark plugs All ModelsThere is one ignition coil per cylinder