The small pulley on the motor should go to the large pulley on the speed reducer. You want to slow things down, so you want the motor pulley to make many turns to get one turn out of the speed reducer. Same goes for the belt from the speed reducer to the sewing machine pulley.
What you have now is attempting to speed up your machine, and reduces the torque so it can't start on its own, needing you to give it a push to get started.