Sumitomo SH125X-3 extreamly slow hydraulics

Hi, I've got a 2003 Sumitimo SH125X-3 excavator and some 7200 hours on it. I got it month ago and have been working with it just maybe 20 hours. There was no maintenance history so first thing after arrival I changed all the fluids and filters, including hydraulic oil.

First problem occurred fairly quickly. The engine was running around 20 minutes and simply shut down. After bleeding fuel line again 20 minutes. I removed bleeding pump and changed worn O-rings and now it goes an hour or so....

Sumitomo SH125X-3 extreamly slow hydraulics

Sumitomo SH125X-3 extreamly slow hydraulics