That part is only one of three pieces that make up the jet holder. There is a the part you mention. There is a spacer or sleeve. There is a double threaded part with an internal and external thread plus a hex. Are all 3 parts on your carb??? Or maybe you never took some of it off???? Just trying to help. :wink2:The jet holder is the part that screws into the carb body and recieves the main jet. .