1971 Evinrude Fisherman 6HP outboards Service Manual, Page 28Get this manual
HIGH TENSION LEAD
SHORTING SWITCH
FIG.4-1Dmomentarily opposes the establishment of reverse flux in the center leg as the poles of the flywheel magnet reach to the center and third leg of the coilAt this precise moment, the breaker pOints are opened by cam on the engine crankshaftThis interrupts the flow of current in the primary current, and the opposed flux in the center leg collapsesTo hasten the collapse, condenser in the primary circuit absorbs the current which would otherwise arc across the opening breaker pointsThe rapid collapse induces current of sufficient voltage in the secondary circuit to arc across the spark plug air gapThe condenser, which acts like storage tank, consists of thin sheets of metal foil separated by insulation, rolled to save space and enclosed in metal caseOne sheet of foil is grounded to the case, the other is connected through an insulated wire to the insulated stationary breaker pointSPARK PLUGS Spark plugs having the proper heat range are very important for peak operation of the motorThis motor is designed to operate with M42K, or J4J spark plugsSpark plugs are classified according to the temperatures at which they are designed to operate, HOT or COLDSee Figure 4-2