IDLER GP-BELT 2534525 - Caterpillar

All 3161 Caterpillar Governors Used In 3500 Series EnginesThe rough handling of 3161 Governors prior to installation can unseat the droop lever from the pivot pin. When this happens both the low and high idle speeds will be 100 to 180 rpm above the factory setting. See Illustrations 1 and 2.
Illustration 1. Location of lever and pivot pin.
Illustration 2. Lever not engaged with pivot pin.A design change is in effect with governors whose date code is 8506 or later. Refer to Illustration 3 for the date code location.
To engage the floating (droop) lever with the pivot pin, remove the governor top cover. See Illustration 3.
Illustration 3. Governor cover. Care must be taken to avoid contamination of the governor. Make sure the governor and the immediate area are clean before removing the cover.Drain enough oil to expose the lever and pin. See Illustration 4.
Illustration 4. Top cover removed.Rotate the output shaft in the "increase" (clockwise) direction. This will make it easier to see the pivot pin. Engage the lever with the pin. See Illustration 5.
Illustration 5. Lever properly engaged with pivot pin.Fill the governor with clean engine oil and install the cover. Refer to SENR3028, Caterpillar 3161 Governor for setup and adjustment. Start and run the engine to make sure that both the high and low idle settings are correct.