Air Governor (Air Compressor Pumps Continuously) (012-018)
B3.9 and B5.9 Series Engines
Section 12 - Compressed Air System - Group 12
NOTE: Be sure the air pressure gauge is accurate and the
supply lines and fittings are in good condition before per-
forming any air pressure checks.
Use a master gauge of known accuracy to check the air
Apply 690 kPa [100 psi] of air pressure to the unloader port.
If the air compressor stops pumping (air pressure stops
rising), the air governor is malfunctioning and must be
repaired or replaced. Refer to the manufacturer's
If the air compressor continues to pump (air pressure con-
tinues to rise), the unloader valve is malfunctioning and
must be repaired or replaced. Refer to the Master Repair
Remove the pipe plugs from the unloader ports used for
accessory air lines.
Install and tighten the accessory air lines.
Connect the line to the unloader valve.