BobCat 753 – ENGINE COMPONENTS AND TESTING – Timing The Injection Pump

Timing the injection pump is done by changing the number of shims between the injection pump and the injection pump mounting surface.

Disconnect the number one cylinder high pressure line from the injection pump.

Disconnect the fuel shut-off linkage (Item 1) [Figure 70-70-26] from the injection pump.

Turn the fuel supply lever (Item 2) [Figure 70-70-26] to the ON position (to the right).

Install a short plastic tube (Item 1) [Figure 70-70-27] in the number one cylinder port of the injection pump. The tube should fit securely in the port and point upward.

Rotate the engine in the direction shown [Figure 70-70-28].

Continue rotation until flywheel timing mark just appears in the window (Item 1) [Figure 70-70-28].

NOTE: The flywheel has two timing marks. The first mark to appear in the window with the rotation shown is 18°. The first mark is used for 753, 763, 773 (Non Turbo) loaders.

Rotate slowly until fuel just starts to flow upward into the plastic tube.

At this instant, the 18° BTDC timing mark on the flywheel should be aligned with the mark in the window (Item 1) [Figure 70-70-28].

Add or subtract shim(s) (Item 1) [Figure 70-70-29] as needed to adjust the fuel delivery timing.

NOTE: Adding or removing one shim will vary the timing by 1.5°. Adding shims retards timing.


Leave a Reply

Your email address will not be published. Required fields are marked *