My gas is freezing over, I hear it's because there is no water getting though it so there might be a airlock somewhere through the system? If so how do I get rid of an airlock. And secondly on top of the air cleaner there is a screw missing where is says idle and when the gas freezes over gas leaker through there. Anybody had a problem like this? Or know where to get a screw for the top of the air cleaner.