I had the same exact problem when I first picked up my pa14 along with my bait tank...It was running but no water was going in...I simply had to take some ocean water and dump it in there...then peddle really quick...after a few runs it works just fine once i peddle quick...there are occasions when the black cap was still on there thoo...
I think it just has to get used to having water run through the pump at first...i mean its not like they put each of these sucker to a test run and then sell it...you might run into again a few more times like I went through but it works great now!