What test on the primer?
You have the blue or black Prestolite ignition system?
Or the Mercury system?
It came with both types??Pics?
Usually the coils don't heatup like a car coil.
In all my time(30+years)I've only seen 1 maybe 2 coils go bad.
Try switching the coils.
Usually weak or no spark is a stator??
Check stator and trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-5V or more), stator reads 680-800 ohms, DVA 180V or more from blue to yellow.
2.If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack.
You need a DVA meter or the attachment for an analog meter.
Get a different gauge and redo the comp test.
You removing all the plugs to do the test?
Your results should be 145-150 not 90