Heres the deal, everyone complains about gurtners because they cant figure out how to clean them.
What you have to do is take the carb apart again. Take the brass nut type think out of the bottom of the carb, then take a small screw driver and remove the retaining nut that is up behind that nut. then with that out take the throttle slide out and take a rod and press the brass aerator out from the top. That is likely your problem. There are a couple very small holes on the side of that piece. Take some fine wire and run it through there and clean them out. Also run a wire through the idle passage. You will be good.