jumpy YW-6 backhoe

[jinmajoe]

I have a YW-6 backhoe attached to a Jinma 284. The hoe runs off of a separate hydraulic pump driven by a PTO. I'm having trouble with the lift on the boom. With the boom only about halfway extended, when I go to lift it no matter how much I try to feather the control it jumps about 3 inches making it very difficult to run a grade.When I extend it all of the way out it's worse, probably jumping a good 6 inches at the bucket. All of the other functions seem to work ok including lowering the boom. I've tried decreasing the rpms but no change. Anyone have any ideas?

 

[Leejohn]

Yes. Check the load check in the boom valve. Might just be it.

 

[jinmajoe]

not sure what the load check is

 

[Leejohn]

I know this is not your valve, but can see where the load check valve is. Yours is more then likely a stack valve.

 

[jinmajoe]

Thanks for the help,
looked up what the load check valve does and can see how a sticky one could cause my problem. Yes I believe that my valves are stacked. Compared to your pic, looks like it is rotated 90 degrees so that the handle is on top and there are 6 of them connected together. I'm trying to attach a pic but can't seem to do it, only inserts text. In between the 2 ports (where the hyd hoses connect) there is a plug where I think the check valve is, but the plug doesn't look like its removable. Will keep trying to send a pic

try this link for a picture of a valve that kind of looks like mine
https://www.surpluscenter.com/produ...+GPM+WALVOIL+JOYSTICK+BACKHOE+HYD+VALVE_L.jpg.

Thanks again