I have this Swan 6242 with a new sac. I've double and triple checked that I have no air leaks nowhere, and the feed is set to the nib, but the latter laways gets soaked with ink immediately when the pen points downwards and that builds up slowly. A minute shake will send ink flying.
It occurred to me that the feed might have been changed from a different pen at some point, but to be honest it's a good tight fit so I can't see it being that.
What are your thoughts?
Video in this link