Just incase that doesn't fix the leak one thing I've often found that happens to super-soakers is that the valve between the pump and the airtank is broken and the air is leaking through that valve and back out were the pump is so fast you cant even get a shot off. Don't know if that helps just though I'd post it.
what do you do if this happens
because i think this is happening to mine i got it to shoot right throw 3 pices of cardbord and thin it did not work after that and it sounds like it near the pump not the tank