HUB-SPROCKET 7T3691 - Caterpillar

Table 1
Quantity     Tools Needed    
1     8T-5160 Gas Regulator Setting Tool    
1     1U-5470 Engine Pressure Group    Gas Pressure to the Gas Pressure Regulator
Ensure that the inlet gas pressure to the gas pressure regulator is sufficient. Table 2 lists the requirements for the inlet gas pressures for different configurations.
Table 2
Requirements for Inlet Gas Pressure to the Gas Pressure Regulator    
Fuel System     Inlet Gas Pressure    
Naturally aspirated engines     8 to 17 kPa (1.2 to 2.5 psi)
1.7 kPa ( 0.25 psi)    
Turbocharged engines
(high-pressure gas)    
83 to 172 kPa (12 to 25 psi)
3.5 kPa ( 0.5 psi)    
Use only properly designated Caterpillar gas pressure regulators.
Regulator Output Gas Pressures
The gas pressure regulator maintains a pressure differential between the air and the fuel that is supplied to the carburetor. After the initial setup, the gas pressure regulator will maintain the pressure differential in response to changes in the air pressure at the carburetor. Refer to the "High and Lower Heating Value Fuels" graphs in order to obtain the differential pressure setting for the correct air/fuel ratio. This graph will provide the optimum value for start-up. The value will also provide stable engine operation with no engine load. Adjusting the Positive Pressure Regulator
Ensure that the gas supply to the regulator is turned off.Note: A water manometer may be used instead of the 1U-5470 Engine Pressure Group .
Attach the lines for the differential pressure gauge of the 1U-5470 Engine Pressure Group .
Illustration 1 g00810413
Typical arrangement for a naturally aspirated engine (1) Plug in the gas line to the carburetor (2) Air filter service indicator on the air cleaner (3) Cap on the gas pressure regulator
Perform the following procedure for a naturally aspirated engine:Remove plug (1) . Remove service indicator (2) from the air cleaner. Attach the lines for the differential pressure gauge of the 1U-5470 Engine Pressure Group into the openings.
Illustration 2 g01948873
Typical arrangement for a turbocharged engine (1) Plug in the gas line to the carburetor (2) Plug in the balance line from the aftercooler (3) Cap on the gas pressure regulator
Perform the following procedure for a turbocharged engine:Remove plugs (1) and (2) . Install the differential pressure gauge for the 1U-5470 Engine Pressure Group into these fittings.
Remove cap (3) .The adjustment screw for the gas pressure regulator is under the cap.
Turn on the gas supply to the gas pressure regulator. Observe the pressure differential.Determine the "High and Lower Heating Value Fuels" graph that is for your engine. To obtain the correct pressure differential, locate the intersection of the BTU value on the line that represents the carburetor that is on your engine. Locate the intersection on the scale that is for the dependent variable to the left of the graph (differential pressure). This graph will provide the optimum value for optimum starting. The value will also provide stable engine operation with no engine load. This setting will generally be between 0.25 to 1.5 kPa (1 to 6 inches of H2O) for