It looks like the pump version was not the problem. I will confirm tomorrow, but according to Defender, I did indeed purchase the pressure limited version of the pump. I don’t think they even sell the non-pressure limited version. The response I got from Jabsco/Xylem customer support said to do this:
The problem with your pump is the Check Valve. What you would need to do is too clean it. Take the six screws out they would are Long then Short in size; the pump will come part in two pieces the motor and lower housing as one piece and the pump head; once you spread the two pieces apart the check valve will usually fall out by itself. The check valve looks like a triangle with suction cups in each corner on one side and the other side theirs a rubber diaphragm in the center; that are machine press in(Take a picture of the check valve “Both Sides”). Take the check valve and place it in a bucket of warm water wait a couple of minutes. While the check valve is soaking; take the head where the suction and the discharge hose hookup and rotate and look inside. You will see a circle in the center a 1/8” edge; take a wet towel and wipe off that edge (Front, Back and Top Edge). Take the Check Valve when it’s submerged pick it up and slush it back and forth in the bucket of water for a couple of minutes (While Submerged). This should clear all the particles. Place the check valve back into the Head of the pump and put it back together. 90% of the time your pump will be back to normal. Seems excessive for a brand new pump but I guess I will have to try it. Dave S/V Aries 1990 C&C 34+ New London, CT
