[Supermario]

I noticed in a couple pictures the suction from tank to pump you had to use a reducer. The larger the suction line the better otherwise the pump is trying to suck through a straw and will drastically effect output.
One other thing that quickly comes to mind is the prv you are using. It is the original valve relief? What is the maximum working pressure of the valve?
The reason I ask is, if you have a circuit that uses a 5,000. Psi relief but you install an attachment like a clam or grapple which only needs let's say 2,200 psi, you can't just turn the 5,000 psi relief way down to the lower pressure. It must be replaced with a lower value relief.
Long story short, maybe the relief is rated too high and working at 275 psi is causing it to not work properly.