Buddy's got a 2002 426. Was running great but now when we go on a ride the idle rises. He adjusts it down but it keeps on going up. Fooled around with the air screw but still does the same thing. He taken the carb apart and cleaned out the jets so we don't think that it is a dirty jet. He has the PowerNow and Boysen cover. Jetting per the instructions. Like I said it was running fine until the last two rides. any suggestions?