Don't these kinds of carburetors incorporate a "slide?" Where there is sliding, there could also be sticking.
I have a tube of Dow Corning 111 silicon grease, which is a lifetime supply though I have used it a great many times. The amount used each time is truly miniscule. I use it to coat electrical bits, which seals out oxygen and prevents corrosion. I use it to coat o-rings, which prolongs their flexibility and service life. It feels like a clear grease, but it goes on more like a dry lube. Once applied and then wiped off, the item is not wet, feels perfectly dry, does not attract dust and remains remarkably slippery forever.