Was trying to pump out a while back and found I couldn't get the suction to work. Wasn't a problem with my boat.

The pumpout station had two hoses and whomever had used the other hose at the station had not closed the valve at the end of the hose... apparently the station was "plumbed" such that it only had one vacuum pump and when you hit the switch, it drew a vacuum on both hoses... with one being open, the other did not work.

Just took a few minutes to figure this out. Thought I would share it in case anyone else ever ran into this issue.