hello,
have a look at these 2 pictures. Is it the "nut" that is marked "G" in the right picture,or the nut that screws into "G" ?
if it is "G",that is the needle and seat valve that shuts fuel flow off when the carb bowl is full. these are available from most parts stores.
If it is the flange nut that is on the fuel line,and screws into "G",then a visit to a carburettor repair place,or a wrecking yard should yield results.(might have to get the whole fuel line with nuts fitted). Or Summit as has already been mentioned by Joe.
regards Rod
