Looks like a brute of a machine! A Rigid 3800 PSI with a Honda engine. It's not mine, I borrowed it. Starts easily and was a powerhouse for about a minute, but then the output fell until it's just a drip. Input water pressure is ok, so I checked the pump reservoir. There's some oil in it, but the dipstick has no marks to indicate how much should be in there. I'm reluctant to overfill it since I'm not familiar with what the consequence might be. The owner doesn't know where the manual is, but he told me it was running ok when he used it about a week ago. He said it has only about 10-to-15 hours on it. Does anyone have an idea what I should check for or where I can get a manual that will indicate how much pump oil should be in it? And what kind of oil that is? Thanks in advance.