If you don't like the handling, or you want to get rid of the spring, try flipping the stem around backwards. Negative tiller on a recumbent is usually Bad News(tm).

Edit: To elaborate a bit - you want your hands to be *behind* the axis of the steerer tube. That way, the weight of your hands on the bars will naturally pull back on them, gently encouraging the steering to center. With the hands in front of the axis, you are left to push on the steering to center it, resulting in squirrely handling.