- Fuel leak
- Incorrect ignition timing
- Incorrect air/fuel ratio
Inspect the fuel system for leaks.
Note: Data from a fuel analysis is required for this procedure.
Use the Digital Diagnostic Tool (DDT) or the Caterpillar Electronic Technician (ET) to check for the correct desired ignition timing.
Adjust the ignition timing according to the recommended timing in the Engine Performance, "Fuel Usage Guide".
An air/fuel mixture that is too lean will increase fuel consumption. A change in the fuel energy content will change the air/fuel ratio. Obtain a fuel analysis. Refer to Operation and Maintenance Manual, "Carburetor Air/Fuel Ratio - Check/Adjust".
The fuel supply pressure must be adequate and stable.
Strike the gas pressure regulator with a soft hammer. If the engine speed changes, inspect the internal parts of the gas pressure regulator for wear. Inspect the gas pressure regulator's diaphragm for leaks. Make sure that the valve moves freely. The valve must seat correctly.
Verify that the exhaust emissions are correct.