HARNESS AS-ENGINE 4354336 - Caterpillar

Introduction
Improper engine operation is often the result of factors other than governor operation. The following paragraphs are provided to give tips about engine problems which can resemble governor problems. Make sure the engine is operating correctly before making any changes in the governor.Attempting to correct engine or load problems with untimely governor adjustment can add to the problems involved with solving improper operation.Most governor problems are corrected by carefully repeating the calibration procedure given in the preceding chapter. There are no adjustments available within the valve.If possible, isolate the governor from the engine to determine if the problem is with the governor and not with the engine or the load on the engine.Governor system faults are usually caused by problems in the installation. Carefully review all the wiring connections, the power supply, and the Flo-Tech Throttle before making any adjustments to the control box. The throttle valve should be considered as a possible control problem if it was not removed during installation.Fuel supply, pressure regulators, carburetors, and ignition conditions can present problems which resemble governor problems.When the Governor is at Fault
Before making any adjustments to the Flo-Tech control review Chapters 3 and 4 to better understand the interrelated workings of the various adjustments and features.If the engine will not start, the following problems may exist:The circuit between terminals 9 and 10 is not closed. The governor is in a shutdown mode if this circuit is open. Jumper the two terminals to make sure the idle speed pot, the speed trim pot (if used), or the shutdown switch is not faulty. Inspect the existing jumper if a shutdown switch, idle speed pot, and speed trim pot are not used.The start fuel limit is preventing adequate air flow.The 12 or 24 volt supply is not present at terminals 1 and 2.Stability Problems
Stability problems not caused by the engine or gas pressure at the carburetor require careful following of the setup procedure provided in Chapter 3. Follow every step when readjusting the control.If the engine oscillates when cold and stabilizes when warm, make sure that the desired (usually idle) dynamics have been selected. Turn the selected dynamics gain pot slightly counterclockwise. Turn the stability pot slightly clockwise if required to maintain stability.Magnetic Pickup
The MPU must provide a minimum pulse signal of 1 volt to the control. It is highly unusual for an MPU to fail if it is properly installed. The most common failure is due to the pickup being screwed in too far and hitting the gear it is sensing. If the MPU does not produce the required signal, check the installation to make sure it is properly located on the sensed wheel. If the MPU is not close enough to the sensed gear it will not produce an adequate signal.Several different sizes of MPUs are available to fit different size gears.Check that the gear is of magnetic material, necessary to drive the MPU. Check the wiring from the MPU to the control.Refer to Manual 82510 Magnetic Pickups and Proximity