Yanmar 4TNV98 Service Manual page 164

3. Note the reading on the dial indicator (Figure 7-
44, (1)). If the reading is less than 2.5mm (0.098
in.), the fuel injection timing is "retarded." If the
dial indicator reading is greater than 2.5mm
(0.098 in.), the fuel injection timing is
"advanced."
Figure 7-44
NOTE: Some model engines require the intake
manifold and fuel injection pump insulator be
removed to access the inner fuel injection pump
retaining nuts.
4. Loosen the nuts fastening the fuel injection pump
to the gear case or front plate. Loosen the rear
bracket(s) on the fuel injection pump.
NOTE: Loosening the high-pressure injection line
nuts on the fuel injection pump may make rotating
the pump easier.
5. Rotate the fuel injection pump until the dial
indicator reads 2.5 mm (0.098 in.).
6. To "advance" the injection timing, rotate the top
of the fuel injection pump away from the engine.
7. To "retard" the injection timing, rotate the top of
the fuel injection pump toward the engine.
8. When the dial indicator reads 2.5 mm (0.098in.)
of pump plunger lift and the target timing mark on
the flywheel aligns with the reference mark on
the flywheel housing or engine back plate, the
injection timing is correct.
4TNV98 & 4TNE98 Diesel Engine
9. Tighten the fuel injection pump mounting nuts
and rear bracket(s).
10. Remove the dial indicator and adapter. Replace
the plug in the pump plunger opening and
tighten it to specification. If removed, install the
intake manifold and pump insulator. Tighten the
high-pressure injection line nuts to specification.
Open the fuel supply valve, remove the clamp
from the fuel return line and prime the fuel
system. Operate the engine and check it for
leaks.
162
Section 4. Fuel System