Chances are it's also a fault in the thread alloy part of the carby.
There's a saying, "it a throw over your shoulder type",
Depending on your supplier and how old the carby is, mine is new and have the exact same problem and it;s the alloy thread, return and replace.
Or buy another cos they cheaper than what it will cost you in fuel running around all over the place trying to fix it.
Just my $0.02 AUD
The point is, if it's returned with a "to the point note" stating the problem, the supplier can liase with the manufacturer, and HOPEFULLY in some time SOON these niggling issues can be ironed out. It's a long shot, but..., Principle.
