I have a 2004 Bayou 250 with a weird problem. Starts right up and idles nicely. Will continue idling nice and slow. A quick spirt on the throttle (without letting it rev up) and it comes back to slow idle. When I rev it up to about 2500 rpm it stays revved at about 1800 rpm. Now, get this, if I turn it off and restart WITHOUT TOUCHING THROTTLE it starts right up and idles nice and slow. (This rules out cable adjustments etc which I have checked anyway) Idle adjustment screw on side of carb is all the way out. (I know this isn't right either) I have re-adjusted the pilot screw at the bottom of the carb a bunch of times and it affects the slow idle but does nothing for the high 1800 rpm idle. Any ideas?