Needed New carb for justy (or Weber DGV)
 

My Justy's Hitachi carb is possessed. Idles when it wants to and at the RPM it wants to IF it decides to.

Completely drives fine other wise. So I went and bought the required adaptor for a weber. (was hopping to find a good used one locally) That didn't work either

SO I'll try you folks here before i pay out north of $220 for a new one.

Anyone have a decent working weber or early Holley 5200 for sale??

Have you tried cleaning or rebuilding it?
 

Apologies if stating the obvious here.

Harbor Freight sells an inexpensive ultrasonic cleaner. Worked great on some motorcycle carbs and a lawnmower carb using some mild detergent. No solvents to attack old rubber or plastic. Turn the carb over a couple of times while immersed to get at all the little passages inside. Watch close and check it frequently at first - sometimes the carb body really is that cheap pot-metal and it’ll start to dissolve! The t-junction for my 4-carb fuel feed did that.

A rebuild kit can also help if any gaskets are leaking or needles/jets are worn. Sounds like your idle screw might be, if cleaning doesn’t clear it up. Never scrape bonded gaskets off phenolic, though, unless you have a resurfacing plate and a lot of patience to polish the scratches back off. I had to replace the phenolic spacer on my old FJ-40 carb after scraping it up.

Vacuum leaks can also muck up an idle, also ignition advance.

Good luck!