Okay, lots of views but no help. How about just this, which could eliminate one possibility before I start throwing parts at the pump?
There is a brass plug in the end of the pump case. The exploded parts breakdown of the J5SH shows a "Nozzle" located behind this plug (http://documentlibrary.xylemappliedw...12/07/BJS+.pdf), #11 on the last page. Maybe the nozzle is cloughed or has a restriction that is causing a loss of pressure. The water tank was pretty groady at the bottom with all the water pumped out. Does the brass plug hold this nozzle in place, or does it screw out with an allen wrench, or ??? How do you properly check to make sure the nozzle is clear?