I have two English beer engines/beer pumps (one is Hi-Gene and the other is Worthside). After a lot of disassembly and repair they both work well, but if I attach them to a keg with more than 3-4 psi, the faucets drip. Is this normal? I realize that bitters are low-carbonation beers, and perhaps that is a designed way to tell you if you have too high a psi. Or maybe I put them back together improperly, or there is some part not functioning properly? Anyone have experience with beer engines who can help answer my questions?