SEAL 7B2126 - Caterpillar

Check the fuel pressure to the gas pressure regulator. Pressure of the Fuel Supply To the Carburetor
The gas pressure regulator maintains a pressure differential between the air 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 air 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 pressure of the fuel supply using the chart found in Special Instructions, REHS9280, "Air/Fuel Ratio Setup for Certified G3306B Engines"Negative Gas Pressure Regulator (Propane)
The engine has a dual fuel system with a negative gas pressure regulator for propane, use the chart found in Special Instructions, REHS9280, "Air/Fuel Ratio Setup for Certified G3306B Engines" to set the engine on propane. Fuel pressure needs set 1.5 to -3 inches of H2O lower than the compressor out pressure.Propane Regulator
The G3306 is equipped with a propane regulator for the propane gas application. The propane regulator controls the pressure to the carburetor, and no adjustments can be made.