Anyone know what would cause the burners in a gas grill to roar like a blow torch. SIL just replaced the burners in a gas grill ( something he has done numerous times ) and now when lit they burn ok for a few seconds then one or more will suddenly pop and start to roar. They are still burning but they roar. Flame is a nice bright blue with no yellow showing. Tried 3 different regulators and same thing with all three.