In Reply to: 9N Spark/No Spark posted by John Parker on January 20, 2019 at 12:05:50:
New parts are no guarantee that they are good parts. That may seem wrong but the fact is replacement parts from China are not getting any better. When there is a problem, just replacing parts is more likely to create new problems than fix anything. Based on repeating identical symptoms this seems like a coil heating up and breaking down. After the coil cools it starts working again.
Look at the ignition resistor and wiring ahead of the coil. Has the resistor been bypassed? If so, that's a good way to quickly fry a new coil.
A bad or improperly rated condenser would cause the points to quickly become pitted and fail. If the faces of the points look nice and smooth, the condenser is good.