Never condemn or adjust the governor pressure settings unless you have checked pressure with an accurate test gauge or a dash gauge that is registering accurately. Standard dash gauges are only required to be accurate to within +/- 10 percent.
Remember the following if adjustment is necessary:
- Turn the adjusting screw counter-clockwise to lower the air pressure setting.
- Turn the addjusting screw clockwise to increase the air pressure setting.
- Be careful not to overadjust. Each quarter turn of the adjusting screw raises or lowers the pressure setting approximately 4 psi.
- The cut-in and cut-out range is not adjustable.
The most common cause of governor failure is contamination. Blow out all attaching lines, hoses, etc when replacing a governor. Make sure the reservoir pressure sensing line is routed from the reservoir so that no contamination may enter the line and pass into the governor. A replacement D-2 air governor can be found here.