Yanmar 4TNV98, Service Manual

Page: 163 / 246

4TNV98 & 4TNE98 Diesel Engine Section 4. Fuel System 161
10. Rotate the crankshaft counter-clockwise until
the dial indicator shows that the injection pump
plunger is at the bottom of its stroke. Rock the
crankshaft back and forth slightly to confirm a
point where the dial indicator shows no
movement. Zero the dial indicator.
11. Slowly rotate the crankshaft clockwise until the
dial indicator shows a pump plunger lift of
2.5mm (0.098 in.).
12. Check the position of the flywheel target timing
mark (previously determined) (Figure7-42, (1))
in relation to the timing reference mark
(Figure7-42, (2)) on the flywheel housing or
engine back plate. If the two marks are aligned,
the fuel injection timing is correct. If the marks
do not align, the fuel injection timing must be
adjusted. See Adjusting Fuel Injection Timing
on page 161.
13. If the injection timing is correct, remove the dial
indicator and adapter. Replace the pump
plunger plug and its copper gasket and tighten
to specifications. Replace the flywheel
inspection port cover. Open the fuel supply
valve and remove the clamp from the fuel
supply hose and the fuel return hose.
14. Prime the fuel system. Operate the engine and
check for leaks.
Adjusting Fuel Injection Timing
If the timing marks did not align when performing
the Checking Fuel Injection Timing on page 158,
the following steps must be performed to properly
time the engine.
1. Leave the dial indicator installed in the fuel
injection pump. Do not disturb the reading on the
dial indicator.
2. Rotate the flywheel until the target timing mark
(Figure7-43, (1)) and the timing reference mark
(Figure7-43, (2)) on the flywheel housing or
back plate are aligned.
IMPORTANT
Do not rotate the crankshaft during the
remainder of this procedure.
Figure 7-43