VALVE GP-MAIN CONTROL 3403466 - Caterpillar

Do not exceed the air pressure of 830 35 kPa (120 5 psi) or damage can occur to the air system components.
Illustration 1 g00596369
(1) Drain valve for the service air tank (2) Drain valve for the air start tank
When opening the drain valve, wear protective gloves, protective face shield, protective clothing and protective shoes.Pressurized air could cause debris to be blown and result in personal injury.
Start the engine. Use the Vital Information Management System (VIMS) to find the pressure when the governor cuts out. Drain the air slowly at drain valve (1) for the service tank until the air pressure drops and the governor activates. Note the cut-in pressure. If the cut-out pressure is not 830 35 kPa (120 5 psi) and the cut-in pressure is not approximately 655 kPa (95 psi), adjust the governor.The VIMS will display system air pressure by entering "550" into the keypad and pressing the "GAUGE" key. This will display the system air pressure. After the test is concluded, press the "OK" key in order to reset the VIMS.
Illustration 2 g00743810
Governor
Remove cover (3) at the top of the governor.
Loosen the adjusting screw locknut under the cover.
Turn the adjusting screw counterclockwise in order to increase the cut-out pressure setting to 830 35 kPa (120 5 psi). If you need to decrease the cut-out pressure setting, turn adjusting screw clockwise.
Tighten the adjusting screw locknut in order to hold this adjustment.After you adjust the governor, check the cut-out pressure. If the cut-out pressure has not changed, then check for bad unloading plungers. If the difference that is between the cut-out pressure and the cut-in pressure is not within the range of the specifications, check for a bad governor.