150cc running problem

[yardog]

I have a 150cc jonway. Hard to start but it will start. Will not idle. Have to work throttle to keep running. It surges up and down with throttle in same position low rpm to high rpm. A few days ago I got it to idle after long warm up and adjusted air/fuel . But yesterday and today it will not idle at all. Have adjusted valve. It has 180 psi compression. It wants to backfire a little. Have put on new intake, fuel, fuel filter, fuel and vacuum hose. I bought it not running, seller said he put on new carb. Do I have bad carb, cdi, coil or other problems you might think of?