John Deere – 1023E, 1025R and 1026R – Adjust Fuel Injection Timing: 3TNM74

[1] – Remove five cap screws from injection pump timing gear cover and remove cover.

[2] –
A new injection pump comes with a timing grid sticker. Each line represents one degree.

Clean off the oil from the timing gear under the pointer in the timing gear cover. Install the sticker (A) on the gear with the center of the grid under the pointer.

[3] –

Loosen the four cap screws (B) securing the injection pump drive gear to the hub. Make sure that the cap screws are loose enough that there is no drag on the injection pump hub. The object is to have the gear move while turning the engine and the injection pump hub remain stationary.

[4] – If the injection pump timing was a lower number than the timing specification, the injection timing is retarded and needs to be advanced.

The following references to direction of rotation are made facing the front of the engine (timing gear end) and turning the crankshaft.

a. To Advance timing rotate the crankshaft counterclockwise.
b. If the injection pump timing was a higher number than the timing specification, the injection timing is advanced and will need to be retarded.
c. To Retard timing rotate the crankshaft clockwise.

[5] – Slowly rotate the crankshaft while watching the pointer on the timing cover and the timing grid sticker on the injection pump gear. Turn it the number of degrees and the direction determined earlier when observing the flywheel grid.

[6] – Tighten the drive gear mounting cap screws to specification.

[7] – Recheck the fuel injection timing. Repeat the check and adjustment procedures until the timing is correct.

[8] – Remove the sticker from the injection pump gear.

[9] – Clean old sealant from injection pump gear cover and timing gear cover.

[10] – Apply small bead of Form-in-Place gasket to injection pump gear cover. Install cover and tighten cap screws to specification.