Combines Master valve poppet assy

the master valve is normally open, the spring goes on top. Does the relay on fuse door have power on both big terminals when the unit is not workingIJ

Not a electrical problem already checked.

Are you saying that only header malfuntions nowIJ What model do you haveIJ If it is only header now you can follow tips lately on that problem for that covers lots of models. Try steering when tring to run function. If other funtions are still bothering your going to have to get valve tore down to have orfices cleaned or tightened ect. likely something easy but may have to pull valve from machine to have it checked out. Good luck