I have an arctic cat 340 fan engine. It says 'arctic cat spirit' on the shroud and looks fairly old. I am helping someone put it on a go-cart and having trouble getting it to idle well. I have determined that the problem is in the carb, and need some info on what is likely the proper carb and baseline jetting for this engine. The carb is a 34mm mikuni, and im not sure if its the stock carb or not. Any help would be appreciated.