Engine System - Petrol (Gasoline)219Service Manual – H aram Captor IIAchieves one but not ALL RPM modes.The approach to diagnosing an engine RPM control problem is to check the inputs to the L series actuator. Ifthe inputs are good and the output is bad, the conclusion is that the actuator is the problem. However, don’tforget that insufficient fuel supply or a restricted exhaust could appear like an RPM control problem if theengine cannot run well enough to achieve a higher RPM.Possible Causes:• Failed Engine Speed Sensor• Actuator linkage• Actuator power supply• Actuator• Wiring• Main Machine ControllerDiagnostic steps1. Visually inspect the linkage between the actuator arm and the carburetor throttle lever.– Is the linkage okay?◦ If not, repair◦ If so, go to next step.2. Check the power and ground supplies to the actuator.– Is there sufficient power and ground?◦ If so, go on to check the Engine RPM Sensor input.◦ If not, repair.3. Check the Engine RPM Sensor input. (Check the AC voltage while the engine is running or checkresistance of sensor through wiring harness from the actuator connector.)– Is the Engine RPM sensor input okay?◦ If so, go on to check the speed request inputs.◦ If not, repair.4. Check the speed request inputs - With the engine running press the engine speed button and check for12v to the throttle 1 wire at the actuator.– Is 12v present on the throttle 1 wire?◦ If so, replace the actuator◦ If not, check the wiring between the main machine controller and the governor controller.◦ If the wiring is okay, check the output coming out of the main machine controller.
