2-strokes are very sensitive to air fuel ratio and the amount of fuel delivered to the combustion chamber. They are also very cold natured. It sounds like the carburetor is not jetted properly. I recommend to find someone that has experience tuning a 2-stroke for now. If you want to continue using a 2-stroke, then you will need to research how to tune a 2 stroke to get the fundamentals. Then it takes trial and error to really learn how to do it. In some cases, the error will cause damage, so get professional help to tune your 2-stroke.