Hey guys new to four posting things in here so be kind. I have a hitachi ex 120-2 I need manuals for and I need to diagnose a problem I am having. When I start it for the first time of the day I have great Hydro power it digs and picks up a full bucket of dirt (1 yard) bucket. But here is where I have the issue after about 30min the hydro power starts to get sluggish and then an hour in and I can't pick the bucket up at all until I shut down for an hour or more. Then it works for 30 min or less so I just shut her down and trying to figure it out. If y'all have a copy of manules that would be awesome I need all of them. She is acting like there is a release valve that is staying open and letting the oil by pass back to the tank after it gets hot.
Just scrolling through and saw this. To me it sounds like a worn pump. Cold fluid will now bypass internally on worn components as much as hot fluid will. Did you ever find the solution to this problem?
Does it bog the engine severly? Lots of black smoke out the exhaust? Or slight load and low pressure? I never saw the original post until it got bumped.