Cart Carb problem

................Is the plug in the rear for the power brake hose.....what do u have the air screws adjusted too............kim....

I have the back plug going to the pcv valve, and the front capped off. I set the screws both at 2.5 turns out for starting, seems to run fine but when it comes down to idle speed around 750-800 rpm it just dies unles you rev it or hold you hand over the top. If I turn in the idle scre to like 1500-2000 it'll stay running......