Hello, this is my first post. My grandfather has an '08 Bayou 250 and it had a low idling, backfiring, and stalling issue. He says it's always been this way since he bought it new (I've never really messed with the thing). I read that the idle screw should be about 1-1/2 turns out and adjusted from there. Well, it was about 4 turns out counting inward and now at 1-1/2 turns it'll start but the idle screams way past 1400 and won't go down. This is with choke, without choke, really no matter what. Any indication? Would anything else be way out of adjustment causing this?