tryin to break in new engine, ruff idle

The exhaust doesn't have to be pushing out black smoke, if the carb is just dripping, due to incorrect float level, or plugged air bleed, will cause symptoms you describe.. more likely carb drip than reluctor gap, or timing out a tooth,, and if dizzy was out 180 degrees, it wouldn't run at all...JMO

sorry,.. just re-read symptoms, and carb wouldn't cause flame outta carb at start-up,, but still think the carb is dripping at fast idle, and prob slow idle too, causing your miss every few seconds.. again JMO