Wind can also be a factor. If the wind is blowing directly into the venting it can blow out the flame. If it's windy where you are, have somebody flip the switches while you stand in front to block the wind and see if it stays lit. If not then you're back to all of the troubleshooting listed above.
2017 Crusader 315
2016 Boston Whaler Montauk 150
Former Montana owner
Colorado Cruiser, Over the Pass and Down the Hill