I've got a new-to-me tao tao like the GK110 (but honestly not 100% sure). I've never had a kart like this before so I'm not sure whats normal.

Starts and runs pretty great, actually, but I think the idle is high. In neutral its pretty loud, sounds like its really going fast. In gear the idle does settle to what sounds like a "normalish" level, however you have to use LOTS of brake to hold it still. I checked or replaced all the cables and the throttle is definitely at neutral.

Is this just a classic case of "idle too high"? If so I'll just try the info in the sticky thread (here)? Or does this sound like something else?

 

No, I haven't read all the article you linked to but you don't touch the mixture screw to lower the idle unless altering the idle stop screw doesn't fix your problem. Set the stop screw with engine warm and check there is some slack in the cable at idle, or the lever/slider won't hit the stop screw for you to adjust. If idle is then too low when the engine is cold, so be it.