GUIDE-VALVE 6I2864 - Caterpillar

Check the fuel pressure before the gas pressure regulator . Table 1 lists the fuel pressure that is required for the gas pressure regulator.
Table 1
Requirements for Fuel Pressure To the Gas Pressure Regulator
Fuel System Pressure
Low pressure gas 10.3 to 34 2 kPa (1.50 to 5 0.25 psi)
High pressure gas
Standard Engine 172 to 207 3.5kPa (25 to 30 0.5psi)
High pressure gas
LE Engine 242 to 275 3.5 kPa (35 to 40 0.5psi) Fuel Differential Pressure of the Fuel Supply To the Carburetor
The gas pressure regulator maintains a pressure differential between the boost and the fuel that is supplied to the carburetor. After setting, the gas pressure regulator will maintain the pressure differential in response to changes in the boost pressure.Use a water manometer for measuring the pressure differential. Obtain the measurement when the engine is operating at high idle rpm. After a load is applied, the fuel pressure will usually decrease by approximately 0.1 to 0.25 kPa (0.50 to 1 inches of H2O). If the performance of the gas pressure regulator is erratic, the gas pressure regulator may require service.Natural Gas
Set the differential of the fuel supply to a maximum of 1 to 1.2 kPa (4 to 4.5 inches of H2O).Check the differential pressure in order to maintain the correct pressure for the fuel that is being burned and the application of the engine. Refer to the engine's Systems Operation/Testing and Adjusting.