ORIGINAL: RTK
Once the reed breaks the engine will not run, you have seen this with the choke run for a few seconds then stop. I'd bet it was cracked and finally gave way. Cracked or warped reeds cause very erratic running.
I would call the new BME and see if they have any. You can make one very easy if you can find the right material. If BME does not have one, call Ralph at rcignitions.com. He will be able to point you in the right direction in finding the correct material. If I had a spare I would send it to ya. Good luck.
Will these notches be a sign of an early crack in my engine's reeds?
Looks like one face of the reeds will be more exposed to develop problems like the one carsh90 is reporting, is that correct?