TUBE AS 3765872 - Caterpillar

(F) Hydraulic Excavators
The set point of the engine in hydraulic excavators can be accurately measured by using the machine hydraulics to load the engine. Refer to the Service Manual for instructions on how to load the engine for testing. The method shown in the Service Manual requires a voltmeter for finding the set point. To use the set point indicator, replace the voltmeter with the indicator. Run the engine with the throttle against the high idle stop and no load on the engine. Slowly apply load to the engine until the OVERRUN light just goes off. Hold the load at this point and read the set point R/MIN. The MULTITACH HOLD SOURCE feature does not have to be used, because the load can be accurately controlled.(G) Tractor-Scrapers, Motor Graders And Log Skidders
This group of machines has either direct drive or a torque converter which puts the engine into a lug condition when used as a stationary load. Therefore, the brakes must be applied while the machine is moving or the implements must be used to apply the load in order to measure the set point.Operate the machine on a level surface with the throttle against the high idle stop and the engine running at maximum R/MIN. Select a transmission gear that will allow the engine to be loaded to LUG with the brakes but will still keep the travel speed to a minimum. Gradually apply the brakes until the OVERRUN light goes off and the set point is reached. Use the MULTITACH HOLD SOURCE feature to read the set point R/MIN. If the LUG light comes on during the test, release the brakes until the OVERRUN light comes on; then again apply the load.An alternate method of loading the engine can only be used if the machine can be worked in dirt or other material. With the throttle against the high idle stop and the engine at maximum R/MIN, load the engine by slowly lowering the blade or other implement as the machine is moving, until the set point is reached. This method is not as successful as applying the brakes because it is difficult to keep the load constant. Because of these varying load conditions, it may be difficult to obtain satisfactory results. However, under acceptable conditions, satisfactory set point measurements can be obtained. Use the MULTITACH HOLD SOURCE feature to read the set point R/MIN.(H) Single Engine Marine Propulsion Installations
To measure the set point, run the boat in open water at full throttle. With the throttle against the high idle stop, allow the boat to come up to full speed and maximum engine R/MIN. The engine should be operating in the OVERRUN condition. If it is not, attempt to remove some load from the engine by running with the wind, changing propeller pitch, or removing weight from the boat. With the engine at full throttle and in OVERRUN, load must be applied to bring the engine R/MIN out of OVERRUN to the set point. Methods of