I have an AR Pump model XTV 3G20, operated by a 5.5 gas engine and it was sold by NorthernStar. It was leaking out the pump head so I replaced the seals and packing but this had no affect on increasing pressure. Although I don't see any leakage out of the bypass when I open the nozzle I suspect the regulator/unloader valve might be the problem. I don't see what else could be causing this. I have a good water supply and the suction screen is clean. A visual inspection of the poppet valves didn't indicate anything wrong. The unloader/regulator valve is a 4 in 1 Northernstar part number 30315. I would like to use a rebuild kit but haven't been able to find one yet. Any thoughts or help on where I'm at and headed would be greatly appreciated.