0397832 JOHNSON FUEL LINE ASSY.

Introduction
Do not perform any of the following procedures without reading and understanding the information first.The Air/Fuel Ratio setup instructions that follow are intended to maintain emissions for fuel with a Lower Heating Value (LHV) of 820 to 1400 BTU/ft3. The engine control strategy is not designed to run on any fuels outside of this range. Maintenance of emissions is not guaranteed on engines that are run on fuels outside of this range. Caterpillar® also recommends adjusting the Air/Fuel Ratio when the gas pressure regulator is serviced or inspected.Set the Natural Gas/Field Gas Fuel Supply Pressure
Regulator inlet pressure should be set between 275 to 414 kPa (40 psi to 60 psi). Regulator outlet pressure should be set so that the carburetor inlet pressure is 1.6 kPa (6.5 inch of H2O).Determining the Ignition Timing
The timing parameters allow the customer to program the ignition timing of the engine to meet the needs for specific applications and installations.Note: Timing will be provided within the Gas Engine Rating Pro (GERP) program.First Desired Timing
The "First Desired Timing" is determined with the methane number of the primary fuel that is being used. Obtain the timing information for the specific fuel and site conditions from the local Caterpillar dealer. The timing can also be obtained using the Caterpillar® Gas Engine Rating Pro (GERP) software program.Note: If the fuel composition at a given site changes greater than five methane points, the timing will need to be reset. Contact the local dealer or use GERP if such a change occurs.A free copy of GERP can be obtained by going to the following link and searching GERP in the search field. More information regarding the GERP program can also be obtained from the website.https://catoilandgas.cat.comGERP can provide the maximum rating capability for conditions at a given site. Use the following procedure to use GERP.
Select "Electric Power" under the "Application" drop-down box.
Select the desired engine by selecting "CG137-12" under the "Engine Model" drop-down box.
In the "Emissions Desc" drop-down box select "EPA Certified".Setting the Ignition Timing
Use the following procedure to set the timing value found in the "Determining Ignition Timing" section using the engine display panel.
Select "Main Menu".
Select "Configure".
Select "All Set Points".
Select "Engine Configuration Parameters".
Select "Timing Control".
Select "Desired Engine Timing".
Select and change the "Desired Engine Timing".Air/Fuel Ratio Setup for Natural Gas/Field Gas
Adjusting the Gas Pressure Regulator
Illustration 1 g03820603
(1) Adjustment screw
Turn adjustment screw (1) counterclockwise until the screw stops. The carburetor is set to full rich.
Illustration 2 g03820605
(2) Cap
Remove cap (2) from the gas pressure regulator.
Start the engine and run at low idle. Adjust the gas pressure regulator using the 8T-5160 Gas Regulator Setting Tool to obtain a pressure of 1.6 kPa (6.5 inch of H2O) from the regulator to the carburetor.Note: Turning the disk clockwise will increase the differential pressure. Turning the disk counterclockwise will decrease the differential pressure.Setting the Air/Fuel Ratio (AFR) Control
Before setting up the AFR control check for the following conditions below.
Verify installation of the catalyst inlet/outlet thermocouples and O2 sensors.
The thermocouples need installed within 30.5 cm (12 inch) from the catalyst and at least 6.4 cm (2.5 inch) into the exhaust stream. The thermocouples should be installed at the bottom of the exhaust pipe on either side of the catalyst.
The O2 sensors need installed within 30.5 cm (12 inch) from the catalyst. The O2 sensors should be installed at the top of the exhaust pipe on either side of the catalyst.
Follow the Application and Installation Guidelines for insulation of the exhaust pipe to the catalyst. The catalyst and the O2 sensors should NOT be insulated.
Since stoichiometric varies with fuel property, the AFR control needs set up to deliver the optimum AFR for the fuel quality at the site. Setting up the AFR control involves adjustment of the input "Desired Emissions Gain Adjustment Percentage" as needed to meet emissions with the fuel quality on site. This input can be adjusted using either Cat® Electronic Technician (ET) or by the Electronic Modular Control Panel (EMCP 4.4). Follow the procedure described in the next section to set this input. The parameter needs set upon first commissioning and thereafter verified & adjusted upon changes in fuel quality. Check the parameter every 750 hours for the initial 3000 service hours and every 1500 hours afterwards to ensure that emissions are met over time. Verify the parameter when the fuel quality changes by 5MN.Desired Emissions Gain Adjustment Percentage Adjustment
With the ECM powered up and the engine not running, check the Malfunction Indication Lamp (MIL) indicator. The MIL light should not be lit to proceed with adjustment of "Desired Emissions Gain Adjustment Percentage" parameter.
Start the engine.
Monitor the coolant and oil temperatures and when appropriate, apply load as needed to reach maximum operating load, ensuring at least 400° C (752° F) at the catalyst inlet and outlet. Ensure that load is maintained as steady as possible. Verify that the catalyst temperatures have stabilized.
If the service tool is connected to the ECM, check if the AFR control is operating in closed loop by following the procedure below.
Illustration 3 g03823277
At the menu bar, go to the "Diagnostics" menu and select "Diagnostic Tests".
Illustration 4 g03823324
Double-click on "System Troubleshooting Settings".
Illustration 5 g03823326
Double-click on "Emissions Feedback Mode". The current value should read "Oxygen Feedback".
Click "Cancel" and exit the screen.Note: Once the service tool is disconnected, the A