I'm going to troubleshoot my buddies Hitachi EX225USRK in the next few weeks and I was looking for some help. When the hydraulic oil is cold he says the machine surges almost like the pilot lever is getting flipped off and on. Then once the hydraulic oil is hot the machine runs great. I will start with the basics by checking all the filters, pilot pressure, and wiring. Where should I go after that, check A sensor and displacement solenoids? Any other common areas that might cause this with oil temperature changes? Do I need to get a DrEX palm pilot for proper troubleshooting? I have attached what I have for a technical manual. Thanks in advance
Welcome to HEF fubard . The machine is more like a Japanese market EX200-5 than a EX200-2 or -3 . You are also going to need EX225USR Troubleshooting manual TT193E which contains the pressure specs , troubleshooting procedures ,schematics, fault codes etc.
I would check the suction screen in the hydraulic oil tank, may be clogged not allowing sufficient amount of to the pumps when cold.