I've just got my hands on a LP Gas carby unit from China for a mower engine etc, just to have a look ,it was $17. with free post.
Looking at the gas converter ,I'm glad I didn't use this type as this one would leak gas if the engine cuts out and it is a small converter so I don't think it would run well on natural gas if you wanted to run a generator off the house gas meter.
The plastic primer button I assume would disintegrate in sunlight as the newer models have been changed to an alloy primer button.
The orange plastic gas switch has 2 holes that go through to the gas so gas could leak out or air mixes with the gas.
I was only planning on using the carby so I can test that out.
This gas unit is for about 5 Hp but I see now they sell a bigger unit now for about 10 hp
