I have been working on a karcher 2500 pressure washer I got in a garage sale. I have taken down the pump and replaced some of the valves and the spill valve. The hose it came with was cracked, but I didn't get a new one until I thought I could get every thing working. Once the pump was put back on it ran fine with the cracked up, but the pressure was lower than I thought it should be. I figured it must be the hose causing my pressure problems, so I got a new one. Ever since I put the new hose on the pressure wash pulsates (It has full pressure for a second or two then it loses pressure for a second or two.) Any ideas what could be causing this?