Kobelco SK60 Mark III valve block

This machine has started to have the main boom lift not wanting to lift. When the engine temp. gets to operating temp. occasionally when you pull back on lever the boom doesn't respond. If you put the lever to rest and then pull back it usually then comes up but sometimes it takes 2 attempts. Sometimes it comes up but very slow. It does it when just digging and also if running a cutter off auxiliary. If the boom sticks when using the cutter when you shut off the cutter the boom will...

Kobelco SK60 Mark III valve block

Kobelco SK60 Mark III valve block