Originally Posted by Soulakala
Most commercially used pumps have CAT pumps, but you'll pay for it. As the previous post said axial pumps are not a great pump, they work but have a limited life. The others out there are some form of piston driven pump, some have a primary and secondary pumping design. Karcher who by the way have been making pumps for years has a rotary disc that activates the pistons others use a camshaft design. My Karcher bought from Costco 16 years ago is only 2600 psi powered by a Honda engine is a workhorse. The only problem is the bi-pass valve wants to hang up once a year after sitting through the winter. Its a 2 minute fix likely caused by my acidic well water.
I think I have the same one and I purchased it in the early 90s and is still going strong with many loan outs to the kids and neighbors.
Soulaka---try hitting the intake and output of the pump with WD40 when done and it will keep that bi-pass from hanging when you fire it up the next time. It was suggested to me a long time ago and has been effective for me. Apparently the WD40 forces the water out of the valve so it doesn't stick.