Yanmar 4LHA-DTP, Operation Manual

Page: 455 / 670

Chapter 3 Fuel Injection Equipment
4. Adjustment of Fuel Injection Pump and Governor
4LHA Series
(A) Slowly r o t a t e the pump in the normal rotation
direction b y hand, and measure the plunger lift
until fuel f l o w stops from the overflow pipe on the
measuring d e v i c e .
Pre-stroke
See separate service data
(5) If the measured pre-stroke is not standard, adjust
by changing the shim thickness between the f lange
of the p l u n g e r barrel and pump body.
mm
Adjusting shims thickness
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
(6) Repeat the above procedure to adjust the pre-
stroke of each cylinder.
(7) After adjustment is completed, insen the gasket,
delivery valve, delivery valve holder and spring.
Tighten the delivery valve holder.
No. of cylinders
3 4
Injection order
t - 2 - 3 - 1
1 - 3 - 4 - 2 - 1
Injection interval
120°
90°
Allowable deviation ± 3 0 '
(3) Readjust the pre-stroke of cylinders that are not
within the allowable deviation (increasing the
adjusting shim thickness makes the injection
timing slower, and decreasing makes it faster).
The change in injection timing effected by the
adjusting shims is as follows:
Change in shim thickness
Change in injection timing
Change in shim thickness
Cam angle
Crank angle
0.1 mm (0.0039 in.)
0.4°
0.8°
Delivery valve holder
tightening torque
39.2-44.1 (4.0~4.5)N(kgO-m
4-3 Adjusting injection timing
After adjusting the pre-stroke for all cylinders, check/
adjust the injection timing.
(1)Set the governor control lever in the operating
position (bring the plunger to the effective injec-
tion range), turn the camshaft clockwise, and
check the injection starting time (FID) of cylinder
No. 1 (start of fuel discharge from the delivery
retainer).
Cylinder No.
Count from the drive side
Direction of rotation Right looking from drive side
(2) Now set the tester needle on the flywheel scale in a
position where it is easy to read, and check the
injection timing several times according to the
injection order.
3-2-33