John Deere — Adjust Fuel Injection Nozzles

Adjustments

From a John Deere service manual covering: 4045, 4045TF120, 6068, 6068TF120, 6068TF250, T06068TF220, T06068TF250, T06068TFM50. Check it applies to your exact model before use.

Applies to: John Deere 4045, John Deere 4045TF120, John Deere 6068, John Deere 6068TF120, John Deere 6068TF250, John Deere POWERTECH 4.5 L & 6.8 L Diesel Engines (4045 / 6068) engine

Procedure

1. Remove nozzle from tester and install in holding fixture.
2. Remove lift adjusting lock nut.
3. Loosen pressure adjusting screw lock nut using JDG949 Nozzle Wrench.
4. Reconnect nozzle to tester with tip pointing downward.
5. Back out lift adjusting screw two or three turns to prevent bottoming.
6. Turn pressure adjusting screw in (clockwise) to increase opening pressure or out to decrease.
7. Remove nozzle and secure in holding fixture; tighten pressure adjusting screw lock nut to 10 N•m (7 lb-ft).
8. Adjust valve lift: turn lift adjusting screw in until valve ceases to open (conventional nozzle).
9. Turn lift adjusting screw out 3/4 turn counterclockwise (based on zero lift); 1/8 turn tolerance permissible.
10. Tighten lift adjusting screw lock nut to 5 N•m (3.5 lb-ft).
11. Recheck nozzle opening pressure and chatter.

Full service-parts list: John Deere 4045 →, John Deere 6068 →, John Deere 6068TF250 →

Source: John Deere service 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.

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