Well, all that usenet stuff is irrelevant. Seems, Basshamme is now having problems with his siphon gun and the point is to help *Bass.

I suppose he is having a similar issue as Steve had. I would also check to make sure the siphon tube is connected, tightly/securely (missing o-ring or seal?), at its upper end, inside the cup. If everything (cleaning, etal) checks out ok, yet still sucking air, only, and not the finish/liquid material, then air may be coming directly from the vent hole to the upper tube, bypassing the liquid in the cup. Suction may be there, inside the cup, but not through the whole length of the tube.

Sonny