1996 merc 5.7 Alpha I Intermittent Spark

[UncleBomb]

I have an intermittent spark from the coil. It ran for 1 hour or so then died abruptly. It starts and runs sometimes on the first turn of the key. It will die shortly after 1min or so. No spark from coil again. Seems like vibration or heat induced problem.

Coil replaced.
Coil wire replaced.
Distributor module replaced.
Run switch bypassed.
Neutral safety working correctly.
Key switch is good.
Harness connector checked and cleaned corrosion.

Any ideas?

I'm gathering info now on the coil measurement to isolate the lack of spark.