Well you could learn to change your own thermocouplers. They only take a couple of minutes. As long as the flame is heating it correctly, it should work right for years. Think about the water heater in a grid house. It will have one thermocoupler for 20+ years!
Think about a wall heater or floor furnace. I have worked on those with a 750 mV thermocouple that is 10 - 25 years old, and they still work great.
It might be the thermocouple is not tight, or not in the correct position within the pilot flame. They only make a fraction of a volt, so if the connection is loose, then it will not transfer the whole 0.085 volts, and the flame will go out.
Also I was working on a buddy's refiregerator in a A-frame trailer. I cleaned out what looked like a white filter in between the pilot and the propane line. Turns out it sort of fell apart in my fingers, then the flame worked right afterwards. I think it was a spider nest. Spiders like the smell of propane, and tend to build a nest near a source of food for their young, normally a pile of dung. But propane has a similar smell to animal dung (Poo). So spiders tend to build a nest in un-lit water heaters and furnaces, and refrigerators.
Good luck solving your problem. My guess is the pilot flame is not large enough, and increasing the pressure to the pilot flame might solve the problem.
Also check your data plate. Chances are that the 120 volt electric element is close to 250 - 300 watts, or 770 - 1000 Btu's per hour. Most gas flames are in the 2,000 - 2,500 BtuH rating, or about twice the heating capacity as the electric elements. So you will get twice the cooling effect on gas than electric.
Hopefully you will get it running right soon!
Fred.
