Yanmar 4LHA-HTP Operation Manual page 455

Chapter 3 Fuel Injection Equipment
4. Adjustment of Fuel Injection Pump and Governor
(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
(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.
Adjusting shims thickness
(6) Repeat t h e above procedure to adjust the pre-
stroke of e a c h cylinder.
(7) After adjustment is completed, insen the gasket,
delivery valve, delivery valve holder and spring.
Tighten the delivery valve holder.
Delivery valve holder
tightening torque
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).
Count from the drive side
Cylinder No.
Direction of rotation
(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.
See separate service data
mm
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
39.2-44.1 (4.0~4.5)N(kgO-m
Right looking from drive side
No. of cylinders
Injection order
Injection interval
Allowable deviation
(3) Readjust the pre-stroke of cylinders that are not
within the allowable deviation
adjusting shim thickness makes
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 shim thickness
0.1 mm (0.0039 in.)
3-2-33
4LHA Series
3 4
t - 2 - 3 - 1
1 - 3 - 4 - 2 - 1
120° 90°
± 3 0 '
(increasing the
the injection
Change in injection timing
Cam angle Crank angle
0.4°
0.8°