Originally Posted by keith.mcginnis
Is it possible a weak coil may fire with the starting fluid, but still be a bad coil?
Yes. Most Stihl coils have a built in rev limiter, that when heading south, can cause an intermittent spark etc.
You also want to make sure the fuel line is in good shape and the primer and lines are good.
But I think you'll find the coil has taken a dump.