I had numerous problems with my 2 stroke kit when I first got it. My first question is, is this a stock carb you put on it? If yes, did you set the needle to two notches from the top? My next question is, did you try turning the idle screw in all the way and then backing it out ~4.5 turns? These things could help. If it is a different carb from the one that belongs, what is the bore on the carb in mm. ? I assume you have the stock carb, so try these things. Also, if you are running a stock plug you may want to change it for an NGK plug. Just try those things out. Good luck, I hope it works!