The wires that are circled are from the trigger. These wires go to the side of the switch boxes and then the green (now yellow)wires go back to the coils. The top wires come down from the stator. Each switch boxes controls the spark for one side of the powerhead. The top switch box will fire 1,3,5 and the bottom box will fire 2,4,6 .
Before I bought a manual . . . I took the motor to Merc Dealer who told me to use it for an anchor :) Two years later the motor hasn't let me down!!
There are only a few electrical components on these older mercs.
http://www.biggerhammer.net/mercury/...200_wiring.jpg
http://www.biggerhammer.net/mercury/
http://outboardparts.com/mercury/tro...eshooting2.htm
http://outboardparts.com/mercury/tro...shooting10.htm