Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Before doing what you suggested, I'd do this first:1. Tapping against the floatchamber with the stub end of a screwdriver2. Remove drain screw of carb #2 and with container underneath open and close the petcock a fuel times and see if you can flush out any debris.3. Add a fuel additive to the gas in your tank like Tunap, Forté, Bardahl.If all this doesn't help, remove floatchamber #2 and clean or polish floatneedle, seat and swivelpin with a very little toothpaste or whatever.
Had exactly same issue caused by use of aftermarket float valves. Changed to OEM one and problem solvedYou could try swapping float valves over between carbs to see if the problem moves first but I would just change the valve.Fiddly but can be done with carbs in situ
My initial thought was the float needle, the OE ones were rubber tipped IIRC, replacements if not original don't have this and as a result don't seal as well