So I bought a Chinese 80/66cc engine off of Ebay, and it ran fine, I got it up to 40 mph. After break-in, I changed the carb out from the stock one to the hp one, and also added a boost bottle. When I started riding, It wouldn't go above 20 mph and the acceleration was super slow compared to what it was before. When I was putting the fuel line in and turned the fuel on, it would only barely flow from the valve, and only when I moved it around. Before I upgraded to the new carb, I once accidentally rode around forgetting to turn on the fuel. All the fuel was used and the line was empty. Now, however, when I tried to see what would happen if I ride with the fuel off, It would remain inside the fuel line, and after a minute of riding the engine would accelerate like it used to, with power, for ~5 seconds and then die, as if there was no fuel, even though there was still fuel in the line. I've tried removing the boost bottle, riding without air filter for a minute, tighten all the nuts and bolts, nothing seems to help. Could anyone offer some advice??