Try adjusting th idle mixture screws in to 1/4 to 3/4 of a turn out from all the way in one at time, leave the ones adjusted in until all four are adjusted that way or adjust them like that with the motor shut off. Make sure and let the motor idle long enough to clean the unburnt gas out of the intake before adjusting them anymore You should be able to kill the motor by shutting the fuel feed off by adjusting the idle mixture screws in to lean to allow the motor to run, make sure the throttle blades are not open enough to allow the motor to run off of the transition or primary cicuits, just the idle circuit Let us know if that works or not