Echo CS 660EVL ignition module

As you can see, this question is actually about a chainsaw, not a mower. My echo CS 660EVL starts and runs fine but after say 10-20 minutes(depending somewhat on ambient temperature,) it stops abruptly just as if I had hit the kill switch and no amount of coaxing will get it to start until it cools off (that may take an hour or more.) Then it will start and run again for a while. If I remove the spark plug and spin the motor, there is no spark so it looks like the ignition module fails when it gets to a certain temperature. If that is the case, I am in trouble as that module is obselete and there doesn't seem to be a substitute available. Does anyone have any clues? Thanks.