Re: 1984 70hp top cylinder spark seems off
If you swapped a known good coil to the mis behaving cylinder, and spark did not improve, i would doubt the coil is to blame.
However, for testing purposes.
It's a good idea to incorporate a continuity test of the coil windings as follows. A coil can be made to fire even with broken windings BUT it will let you down at the worse possible moment.
(Magneto Capacitance Discharge Coils - Continuity Test))
(J. Reeves)
Check the continuity of the ignition coils. Remove the primary orange wire from whatever it's connected to. It may be connected to a powerpack screw type terminal, a rubber plug connector, or it may simply plug onto a small boss terminal of the coil itself.
Connect the black lead of a ohm meter to the spark plug boot terminal, then with the red ohm meter lead, touch the ground of the coil or the powerhead itself if the coil is still installed.
Then touch (still with the red lead) the orange wire if it's attached to the coil, or if it's not attached, touch the primary stud of the coil. You should get a reading on both touches (contacts). If not, check the spring terminal inside the rubber boots of the spark plug wire. Poor or no continuity of a coil is one reason for s/plug fouling.
urple :38-42 :0.6V or more Connected