If the Boom Arm moves when the Boom Control Knob is at “0”, the Boom Control
Valve needs to be adjusted.
There are 2 set screws to adjust this through the Access Holes(3) in the Valve Cover Plate.
If the boom moves up, make sure the Boom Control Knob is at "0", then slowly rotate the UP CONTROL screw
clockwise with a 1/8" hex wrench just until the boom stops moving. Do not make tight.
If the boom moves down, make sure the Boom Control Knob is at "0", then rotate the DOWN CONTROL screw
clockwise just until the boom stops moving. Do not make tight.
Warning: Making the adjustment
screws too tight could damage the valve. If boom drift can not be stopped, the Valve Seals may need to be replaced