Ran again today, runs super strong, lightning quick throttle response and again about the 13 min. mark started to bang again, not quite as load or strong a few times at idle. Crack throttle open and it roars and no bang.
That might be the ticket, with my 2" headers some of the wires are right up on the exhaust. I saw that early on an I am running each with high quality plug "socks"Misfiring and raw gas is burning/ popping in the hot exhaust. You have a misfire, bad plugs or bad wires, 13 minutes is the time it takes to get the exhaust tubing hot.
Yes, I have been charging battery up between runs and it reads about 13.67 before startingI gotta ask... are you charging the battery back up between these runs??? 12.53 volts certainly doesn't impress me. A static battery, fully charged, should read more than that!
I think it might be, I got from Mancini a bit ago, but it is brand new and just put on for this build. I'll need to check that for sure tomorrow. So you think it's rushing fuel past floats...clear filter is full.