I don't think I saw this, but I was having the same issue one time and I put a jug of gas with the supply side hose into it (disconnected the hose from the pump and installed a long hose on the pump to reach the jug) to see if there was a block before the pump. In my case there was, so I got lucky that I figured it out before I started throwing parts at it - which I have been know to do
