I have a very good running old Enya 46 4 stroke. It has good idel and high end. My problem is I cannot get the barrel on the carb to close down all the way to shut down the motor. I cannot find the manual and have not even seen it in a few years. Does anyone know what screw adjust the threw on to carb barrel? I have three scews on the carb. One on the bottom and two on the top. One of the screws on the top is for air flow at low end. I have tried to adjust the other two scews a little at a time and check the travel of the carb barrel and cannot see any change. Help please![]

Thanks