I have a kamatsu PC27MR - 3 mini. My boom raises on its own as soon as it starts. I cannot control it,up or down , Everything else works as it should it does have 6000 hours. Any help would be appreciated.
Raises even with the safety bar not in the operate position? Boom valve might be jammed.
Yes it raises, Safety bar up or down?
You're going to want to disconnect the boom hoses at the control valve. Look in the ports to see if you can physically see debris holding the spool to one side or the other. Maybe take the spool end caps off as well. See if you can exercise the spool back and forth with your fingers. Avoid using screwdrivers and punches. You don't want to damage the spool or housing. Let us know what you find.
Most machines have a safety bar, handle or something that keeps you in the cab, controls swung down into position. out of position it should engage a safety that prevents control inputs to any function or at least the boom and swing functions. This would eliminate a 'stuck control' situation versus a stuck spool valve situation
I should not have had a? Behind the safety bar upper down sentence. The boom raises No matter what position the safety bar is in, You cannot control it up or down.
I think @funwithfuel is spot on as far as the next steps. You might want to rig up a shop vac to your hydraulic tank filler to keep oil from running everyplace as you disconnect lines.