I would try to check whether it is out on the "left and right" alignment or the "up and down". If it is the former then you will either have to file the end of the tap so it can further in or shim to bring it out. If it is the latter then there is a fair chance that the plastic lever is not on properly and stopping the tap from closing properly. I had an airsporter that was doing this and on close inspection, the tap lever was just catching on the cylinder and stopping the tap from being fully closed.