I read questions and answers and it seems to me that it may be the covered venturi, because everything is impeccable, there is little use of the heater. I am not a technician. I found that my venturi is made of bronze, not plastic, and I don't know how to put a hand to try uncovering tartar and see what it is. I need help with the bronze venturi !!!!!!!!!

Hi, thanks for the hand. Yesterday I took a seat as far as I could with the venturi, and there was nothing tartar, there was only a small water pipe shank. I tried it, because I could not disassemble everything, with a crochet hook, and the spring responded well. It must be the diaphragm no more. Here we go !!!!!!!!!!!!!!