I need alot of help. I got a broken down moped from a family friend that had no key and no battery. I stripped the wire harness because it was old and not connected. I made a redneak version of the wire harness that consisted of the killswitch and the electric start. the other problem with it was the carb is a 2 stage and the idle jet (not sure if I'm using the right words bit it was the small one) was permanently clogged. I ordered a new carb but it was too big for the engine and it backfired and overrevved. I took the idle jet from the big carb and put it in the stock one and it ran perfect for a bit. I'll try to explain the best I can but the engine will shift between 2 'modes' the first one being it runs perfectly and the second is hard to explain. it will over idle so that you can't have it stopped while running because you will be pulled with it and if you throttle more than 15% it will sound like its not getting gas and bog down. it constantly accelerates without the throttle. its not cable problems because it works fine so I have no idea. I don't have a photo but I can take one soon. the carb doesn't have a air filter but I don't think that's it. please help I am in mental pain.