Yanmar 4TNV98 Service Manual page 197

4. Install Yanmar timing tool (Figure7-49, (1)), into
the port where the bolt was removed. This will
provide a reading of the injection pump plunger
lift.
Figure 7-49
5. Rotate the engine about 25° in the
counterclockwise direction. The dial indicator
should move for approximately the first 10° of
engine rotation and then stop. When you reach
approximately the 25° position, rotate the engine
slightly back and forth to make sure the needle
of the dial indicator does not move.
6. Set the dial indicator to "0".
7. Rotate the engine in the clockwise rotation until
the timing mark on the crankshaft pulley is
aligned with the mark at 4, 6 and 8.5° ATDC
(After Top Dead Center) on the timing grid on the
gear case cover.
8. 5deg ATDC.8.If the injection timing is correct, the
dial indicator should read 0.038 - 0.041 in (0.97 -
1.03 mm).
9. If the injection timing is not correct, loosen the
three fuel Injection pump mounting nuts and the
bolts retaining the bottom / rear L-shaped
injection pump mounting brackets. Rotate the
injection pump to bring the dial indicator reading
into the correct range.
4TNV98 & 4TNE98 Diesel Engine
10. Then retighten the pump mounting nuts and the
mounting bracket bolts.
NOTE: Rotating the injection pump away from the
engine advances the injection timing. Rotating the
injection pump toward the engine retards the
injection timing.
11. Remove the timing tool and dial indicator.
Replace and tighten the center bolt and sealing
washer into the injection pump port.
195
Section 4. Fuel System