John Deere — Adjusting Variable Speed (Droop) on Generator Set Engines (Stanadyne Mechanical Injection Pumps Only)
Adjustments · Fuel injection pump governor
From a John Deere owner's manual covering: 4045TF120, 6068HF158, 6068TF120, 6068TF250. Check it applies to your exact model before use.
Applies to: John Deere 4045TF120, John Deere 6068TF120, John Deere 6068TF250
Procedure
- Warm engine to normal operating temperature.
- When necessary, disconnect throttle linkage or cable.
- Adjust slow idle and adjust fast idle speed when necessary.
- Run engine at fast idle, then apply load until reaching rated speed.
- Check power. Adjust with the screw if needed.
- Remove load from engine.
- Again check and adjust fast idle if the droop screw has been turned.
- Repeat procedure until both the engine power and the fast idle speed are correct.
- Reinstall throttle linkage if previously removed.
Full service-parts list: John Deere 6068TF250 →
Source: John Deere owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.