AnEv Yes the burner does not have a separate pilot. The main flame contacts the thermocouple continuously. The problem is that starting is not consistent. I would have replaced the TC if that tiny burner screw could have been removed. It is about 1/4 inch from the plywood. Bryants and Lauralhurst give reasonable details about the thermocouple. It is not removable or easily accessible. It is 'captured' within the lower box. The nut that holds the TC in place is also not accessible without removing the burner!!!
I have already built a wind shield to stop flame blowout and I could have installed a better accessible holddown if I needed to. Thanks again.