Who knows all about pressure washer pumps?
I fired my pressure washer up this past weekend and it's not working properly. When the engine isn't running, I have normal flow through the pump when the trigger is squeezed. When the engine and pump are running, I get nothing out at all. I disconnected the output hose and the problem is the same so it's definitely an internal pump problem.
I did a lot of googling and reading this morning and there seems to be disagreement on what might be wrong. Most of what I read said the unloader valve would cause this if sticking but one or two sources say that if the unloader valve is sticking I wouldn't have any flow through the pump when it's not running, either. There were also several comments about a sticking inlet valve not allowing water into the pump but I'm not really sure what they're talking about as I saw no "inlet" valve other than the check valves.
I did disassemble the valve body and everything looks like new inside. No mineral buildup at all. All six check valves were fine and I found nothing wrong with the unloader valve. The pump input shaft turns freely and the three pistons move freely as the pump turns. I reassembled everything and still no change.
By the way, it was winterized and actually lived in the garage last winter so no freezing.