1976 Johnson 2HP 2R76 Outboard Motor Service Manual, Page 28Get this manual
4-3 To 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 motorSpark plugs ar classified according to the temperatures at which they are designed to operate, HOT or COLDSee Figure 4-2Selection of the correct spark plug depends on the type of service to which it is subjectedUnless the spark plug is properly suited to the motor, trouble may arise which might be interpreted as carburetor difficultyVery low trolling speeds will tend to foul plugs due to the oil not burning from the coreHowever, at full throttle with hotter plug, the operating temperature may be too high, resulting in preignitionAn extreme temperature range will be difficult to control with one plugSpark plugs furnished with the motor are selected for average serviceSee Section 2, SpecificationsFigure 4-1ECondenser Exploded RUBBER INSULATOR INSULATION