The scenario: I got off the bus in Louisville and the 40 started up just fine with about half choke. I cruised the short distance to the Conoco to fuel up and afterwards when I went to crank it, my starter clicked (normal) so I kept cranking until it fired. When it caught, the loudest backfire I've ever heard occurred, probably nearly killing the elderly couple next to me (she screamed as loud as the backfire and I assume everyone over 50 has a weak heart).
The choke was still half out, the engine was not all the way warm but I probably didn't need any choke at this point.
Did I cause this by having the choke engaged? Should I dig for further cause or ignore it unless it happens again? If my backfire causes so done else to have a heart attack, am I liable?