Yanmar YM276 Service Manual page 494

230-1 0-1 0
Fuel System
5. If the top clearance of the plunger is greater than the specified
-
valve, remove the plunger guide (A), and insert a plunger stroke
adjusting shim (61 between the lower plunger spring retainer
(C)
and the plunger guide. Adjust each cylinder i n a similar manner.
I f a measuring adaptor is not available, insert a shim with the
same thickness as the one removed. Measure the injection
timing of all cylinders, and make the plunger fop clearance
of each cylinder uniform.
A
-
Plungar Guide
B -Shims
C
-
Lower Spring Retainer
D
-
P1ung.r
PLUNGER TOP CLEARANCE ADJUSTING SHIM
SPECIFICATIONS
Parts
Code
Thicknarr
. . . . . . . . . . . . . . . . .
174307.51710 0.1 m m (0.004 in.)
174307-51720
. . . . . . . . . . . . . . . . .
0.2 mm (0.008 in.)
6. Install delivery valve holder after measuring. Tighten the holder
39 t o 44 Nm (4 t o 4.5 kgm) (29 t o 33 ft-lbs).
,
TESTING PRESSURE OF DELIVERY VALVE
1. Attach a 98 Mpa 11000 kgf/cm21 (14220 psi) pressure gauge
to the delivery valve holder.
2. Operate pump tester and give a pressure about 11.76 Mpa (120
kgflcm2) (1700 psi) t o the delivery valve.
3. Measure the time required for the pressure t o drop from 9.8
Mpa (100 kgflcrn2) (1422 psi) t o 8.82 Mpa (90 kgf/cm2) (1278
psi). Compare measurement taken t o the following specifica-
tions.
DELIVERY VALVE
SPECIFICATION
Time Allowance
.......................
Pressure drop Max. 5 sec.
. . . . . . . . . . . . . . . . . .
Testing Pump Speed 200
RPM
TESTING PLUNGER PRESSURE LEAK
1. Attach a 9 8 Mpa (1000 kgf/cm2) (14000 psi) pressure gauge
t o the delivery valve holder.
2. Increase pressure about 49 Mpa (500 kgf/cm2) (7000 psi) and
check f o r fuel leaks from the delivery valve holder and injection
pipe connection. Make sure does not drop instantly.
,--
SME2760[71-glM YM276 and 276D
Kinornoto, Prinfed in J a P n