Hello! I tried searching around here before making this post, but couldn't quite find the same symptoms that my engine was having... I have what I'd assume is an unbranded 49cc Huasheng 142f, and it suddenly started acting a bit weird... Before today, it would idle well, and had plenty of power. The overall gear ratio is set to top out at about 32MPH @ ~7500RPM, and it has done so consistently... But today, after taking it for a rather short spin, the engine seemed to want to idle very high. If I lifted the rear wheel up, the engine would spin it faster until it hit maybe 3500-4500 RPM... Even if I took the idle screw completely off, it would continue to idle very high. Turning the choke on or off made seemingly no difference. I tried riding it again, and it still seems to have the same top end power/speed, though I think it sounds a little different (or maybe it's all in my head)... My first thought was to adjust the mixture screw on the left side. I screwed it inwards quite a bit until the idle lowered, but now it's extremely erratic. It will idle well for a second, jump up high, or very low, and repeat in no specific order, until it finally dies I've tried taking the carb apart and cleaning out the low speed jet, but to no avail. I did notice that the gasket between the carb and the engine seemed a bit rough, but I'm not sure if that's truly the issue, because as far as I'm aware, that wouldn't explain a high idle. Another small but possibly important detail... Sometimes when the engine dies or fails to start, it'll make a small "puff" noise and the carb shoots mist/smoke backwards. I'm not really sure what the issue is, but I'm fairly certain it's something to do with the carburetor, or possibly the valves. Any help or redirects to similar threads would be appreciated! I was planning to replace the carb with an NT setup, but it would save me money to keep it running stock for now.