re: Backyard Natural Gas to Propane conversion?

just to clear; you are getting gas ie hearing it come through the valve? Assuming you are, then almost certainly your grill is set up for propane and since it doesn't seem to be working as is then you need to change orifices. If you have decent quality gill give them a call to get pointed in the right direction as far as converting it. A little surprised that it doesn't work at all even without converting though.