Yanmar 3TNV82A-B Service Manual page 273

Checking and Adjusting Fuel Injection Timing
• EXAMPLE: If the distance between the two
"longer" marks is approximately 2.0 cm and the
distance from the TDC mark is approximately
4.0 cm, the answer is approximately 2. This
indicates there is 10° (2 x 5°) between the TDC
mark and the first "longer" mark on the timing
grid. That means the first "longer" mark on the
timing grid indicates 10° BTDC, the second
"longer" mark indicates 15° BTDC and the third
timing mark indicates 20° BTDC. If the answer
is 3, that indicates there is 15° (3 x 15°)
between the TDC mark and the first "longer"
mark and that the first "longer" mark indicates
15° BTDC with the second and third "longer"
marks indicating 20° BTDC and 25° BTDC
respectively.
8. Highlight the timing reference mark
(Figure 7-44, (2)) on the flywheel housing or
engine back plate (Figure 7-45, (2)). Highlight
the TDC (Top Dead Center) mark
(Figure 7-44, (1)) on the flywheel.
9. Highlight the target timing mark
(Figure 7-45, (1)) on the flywheel as calculated
in Determining the Fuel Injection Timing
Specification on page 7-30.
(2)
Figure 7-44
TNV DI Service Manual
(1)
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
2.5 mm (0.098 in.).
0002065
12. Check the position of the flywheel target timing
mark (previously determined) (Figure 7-45, (1))
in relation to the timing reference mark
(Figure 7-45, (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 7-34.
FUEL SYSTEM
(2)
(1)
Figure 7-45
(1)
0002066
(2)
0002142
7-33