[JP Noonan]

Do you mean cuts out and dies after it warms up and goes to 3500? Or dose it sputter and buck badly? Or will it refuse to go above 3500? My guess is either the dizzy or the thottle position sensor (TPS). If the dizzy broke an advance wieght spring or, like mine, became rusty and locked up. If the TPS is badly worn it usally bucks at a certain RPM but is fine above and below. I would pull out the dizzy, if you do it right you don't have to retime the motor upon installation. Then check the FI points and advance weights, and look for a worn out shaft and cam lobes.