I have a 2000 prarie and have been having problems with it running very cold. It runs pretty much fine after it gets warmed up but will still bog a little under hard acceleration when going slow. I have cleaned the carb and found a really long spring on the diaphragm. It was broken so I went to the dealer to get a new one; they did not have a new one but gave me an old one which was also about to break. I am no atv carb expert, but I was wondering if the spring being broken might be part of the problem. The spring is so long it needs a sleeve to keep it from binding to the side. Judging from the two I saw (the original one and the one the dealer gave me) it seems it might be a problem. I have also tried adjusting the screw on the bottom with no luck. Anyone else have any ideas?