Gas accumulating in the intake is a design problem with updraft carbs. That's why every one I've ever seen has a small drain hole in the lowest part of the intake elbow so the gas can run out. (except for Marine models which are plugged so the gas can't drain into the bilge and blow up the whole darn boat)
Your's may be blocked.
I have never seen an updraft that had an accelerator pump either, for obvious reasons.
Next time you have one that catches fire, pull the choke out and/or stuff a shop rag in it.
I always keep a CO2 extinguisher close to the engine area of my shop, won't damage anything and no clean up problem. On the other wall I keep the dry chemical for electrical fires or big fluid spills.
It's a good idea to fix the problems so it doesn't fire back through the carb in the first place.