What is under a welch plug? And what does it do? My Stihl dealer says it takes a special tool and he don`t pull them out at all even though he has the tool.
Do a search on 'WELCH' and you will get a bunch of info.
There can be numerous items under those plugs depending on the carb.
You can poke or drill a small hole in them and pop/pry them out.
Some of the carb manufacturers sites have info on removing and replacing them.