If you want it to operate as designed, there are 550 places in your state to buy real gas...
http://pure-gas.org/index.jsp?stateprov=NC
Edit: I forgot to mention that I believe your a/f adjustment screw is just plugged, and can be accessed by drilling and removing it (the plug). Or you can go to fleabay, and buy a brand new, adjustable carb, for your 50cc for just under $23.00, that includes free shipping.