PLATE-PORT 1687321 - Caterpillar

1.1 Liter Family Of EnginesReference: See article titled "New Fuel Setting Screw Cover And Bolt" for 1.1 Liter Family Of Engines in this issue.Description of Change: Several improvements have been made to the engine rack control assemblies (see Illustration 1). These include: ... A redesigned clamp assembly. The worm gear connection between the clamp and the fuel setting screw has been removed. The new design (Illustration 2) eliminates the potential for backlash between the clamp and the fuel setting screw. In the former design (Illustration 3), backlash at the worm gear connection could result in low idle surge on earlier 1.1 Liter Engines.... Some of the improved control shafts do NOT have a 5C8312 Locknut on the fuel setting screw (see Illustration 2). The clamp in these control shafts have a lock-type thread that engages tightly with the fuel setting screw, and the locknut in not necessary. The fuel setting screw in these control shafts, without locknuts, has a noticeable resistance to turning, when adjusting the fuel setting. However, because of difficulty in controlling the amount of thread interference, the lock-type thread in the clamp is on longer used with the fuel setting screw, and the locknut in now in production again.Adaptable To: The part numbers for the improved 7C1514 (3114 Engines) and 7C1516 (3116 Engines) Rack Control Assemblies have not changed. See the chart for the effectivity of this change. This change is also adaptable to first production. The rack control assemblies are NOT adjustable EXCEPT for fuel setting and injector synchronization.
Illustration 1. 7C1516 Rack Control Assembly (similar to the 7C1514 Rack Control Assembly).
Illustration 2. Section A-A rotated 90° clockwise. (1) New clamp assembly. (2) New setscrew (fuel adjustment). Viewed from rear of engine.
Illustration 3. (3) Former setscrew (fuel adjustment). (4) Former clamp assembly. Viewed from rear of engine.