FRAME AS 1641331 - Caterpillar

Illustration 1. New parts in the governor and fuel injection pump groups for all models.
Illustration 2. New linkage and parts in the governor groups (internal view of governor lever where connected to the new control). For 3406B Engines in Driltech Drill Rigs, see Illustration 3.
Illustration 3. New linkage and parts in the governor group for only 3406B Engines with the 7C6614 Engine Arrangement in Driltech Drill Rigs. Shown is an internal view of the governor lever connected to the new control.A Service Manual Supplement will cover system operation, testing and adjusting, and disassembly and assembly of the control linkage.
If service work is done on the new control, there are two differences to remember that apply ONLY to the drill rig application.
... The control must be pressurized to 105 kPa (15 psi) in order to check the static fuel setting. This can be done with air pressure and a suitable pressure regulating valve. Or, the fabricated test kit (FT1829) can be used.
... Also, in the governor linkage, a special 7C8219 Lever Assembly is used. See Illustration 3. This lever assembly uses a 7C8220 Piston and has NO spring. These changes inside the governor cause the maximum fuel setting at startup and during low boost to be limited to the fuel ratio control setting. These changes also help engine starting in this application.