B38

I had to turn my boat around in the slip, start 406 stroker with 118 hours since major rebuild and turned boat around with no problem. shut off and do my thing, about a 1 hour later I started again to go for a cruise, upon startup, it kicked back and backfired, retry, and engine now has a miss. Reved up a tad to clean out with no luck. Smelled unburnt fuel, Got pissed off and left dock with miss. Got about 1/2 mile away from dock and it cleaned out with no problems after that. What happened, Reversion, or Q-Jet dumping gas in Cilinders, I just can't see or reach any plugs without a major tear down. I plan to go to the Bahamas with this boat in October, this freeked me out with a bad thought, will this happen again in the Bahamas. I need all your thoughts to resolve my freeking out. I used all stainless plugs Mr 43 T.
This motor uses no oil, run awesome till this kickback problem yesterday. Is it just a fowled plug do to gas leaking down, or reversion. Oh yeah, I have stainless valves. Your thoughts. Mr. B3