I have a C116 BE longvie water heater and it has been a while since the selector does not regulate the size of the flame well, in the first point it is very low and in the rest it is excessively high. Full maintenance, serpentine cleaning, burners, diaphragm replacement and still the same. Do not know if there is something that should be done in the part of the regulator of the gas column? It also has a screw that could be of regulation in the part of the burners, but it is quite taken and I don't know what its function is.

I disassembled the selector valve and indeed the piece you mentioned seems very worn, the first points are practically all equal in height, attached the photo to give me your opinion if you can. These days I will see if I get a spare in a large gas business