Hey MO! My engine didn’t run right even after I cleaned the carb thoroughly, so I bought a new one from ScrappyDog, and it still doesn’t run right! I know it’s the carb, it has to be. I’m an experienced mechanic of 20 years, and have build race engines before, so I know what I”m talking about. I’m not a happy camper. I think you sold me a defective carb.
While defective parts do happen, especially in the super high production volumes that Chinese product are made, perhaps something else is at fault. In a scooter, there is a vacuum operated fuel valve called a petcock. It has been found that when the diaphragm in the valves is defective, it allows fuel to run through it, directly into the vacuum line, which is attached to the intake manifold. This causes a seriously high rich fuel mixture ratio, making for very poor running, if at all. Usually the symptoms are bike will only run at very full throttle, and then only poorly. Also may run only at idle, and quit as soon as throttle is opened. While we are in the business of selling parts, it may be that you could save some money and get a new petcock. I’d recommend checking to see if there is fuel in the vacuum line. If there is any at all, that’s what it is!