Doug... we can eliminate the t'stat as a problem. ( As you suggested earlier) I bypassed all the controls on the LP side. Ran a tube from the unit cutoff valve directly to the burner assembly. Now only things involved are the LP tank, regulator, cutoff valve and Orifice. I had a manometer connected at the test port. 11 inch water column. Manually lit the flame. This arrangement should allow the burner to operate at full capacity with out any complications.
refer temp had been maintained at 20* to 22* on electric for at least 12 hours.
When switched to gas the refer temp went from 20* to 35* in 6 hours. Those temps don't sound bad but I know from earlier camping trips that the temp would got to 45 of 50 degrees if continuing on LP.
I increased the LP pressure from 11 to 13 and then to 15 with no change in flame appearance. Nor did the increased pressures raise the boiler temperatures.
Someone earlier had suggested that even though the pressure is correct that the flow might not be sufficient. I don't know how to test the flow but at this point I have to assume that the orifice is not big enough to allow a larger flame but a larger flame is needed to produce more heat.
It is ironic that with all this heat I'm wanting more heat to cool my refer.