Last, it seems to work ok on the ac and dc but the lpg is very weak. Any ideas?
You need to use a manometer to check that there is enough gas pressure at the orfice. I beleive that it is around 11 cm of water pressure. If everything is working on 110 volt, then I would check this out. These fridges usually require yearly maintenance. Spiders like the smell of LP gas and can form nests that can plug up the works. As well as you may have a partially blocked orfice. Do not go poking at the orfice with anything metal, you can damage them. They need to be cleaned with solvent. Sometimes just a good shot of air and blow everything out behind the fridge
is needed. If the 110 volt is keeping the fridge cold then I think you can ruke out the spiral flue that runs down the middle of the chimney.
LP gas is alowed to have a certain percentage of oil in it. This can settle out of the LP gas and end up blocking a line. The you have to disconect your lines from each appliance and blow from the furthest one first and work your way back to the tanks. First you have to disconnect the line just after the regulator. You do not want to blow any oil into that. If your stove flame is burning fine and has a steady bluish flame then I would start with the orfice. If the flame at the stove is not a good flame and bounces alot, and is not a bluish tinge then I would start at the regulator and replace that first. Regulators go on a regular basis. So that maybe the problem. Keep us posted