That doesn't sound right. You better have a spare carb...

You have 3 screws. An idle set, a low-speed mixture and a high-speed mixture. The picture you sent shows what look to be the idle set screw and the low speed air mixture. Not sure which is which but it seems to be you need to figure that out first if nothing is blocked.

If you idle is not set right, you may be trying to adjust the air-bleed mixture to a place where the idle is not...if you know what I mean.

The idle set screw will just keep increasing the idle but when the engine is running, the air mixture may "sound" like its doing the same thing. You need to find the documentation!!...but you have to get the low-speed air mixture and high-speed fuel mixture in the "ball-park" first. Typically 1 1/2-2 turns out on the high speed mix and 2 turns out on the low speed mix. Then I would adjust the idle up fairly high...because that screw is probably not documented. Follow the directions to adjust the low speed air mix, then follow the instructions to adjust the high speed needle setting. Then lower the idle to what you expect...and double check the other two settings.

I believe someone has screwed up your idle set screw.