Yanmar 4JH2E Service Manual page 91

Chapter 3 Fuel Injection Equipment
4. Adjustment of Fuel Injection Pump and Governor
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~-4/H
Series
4·4 Plunger pressure test
(1) Mount the pressure gauge to the delivery retainer of
the cylinder to be tested.
Max. pressure gauge reading
Connecting screw dimensions
1000 kgfcm
1
(14223
lbnn. ')
M12
x
1.5
(2) Set the governor control lever to the stop position,
operate the injection pump at about 200 rpm, and make
sure that the pressure gauge reading is 500 kg/cm'
(7110 lb/in.') or more while lightly moving the control
pinion gear towards full throttle (drive side) from the
pump.
Replace the plunger if the pressure does not reach this
value.
(3) Immediately release the gear after the pressure rises to
stop injection.
Al the same time, check to see that oil is not leaking
from the delivery retainer or fuel injection piping, and
that there is no extreme drop in pressure.
4·5 Delivery valve pressure test
(1) Perform the plunger pressure test in the same way,
bringing the pressure to about 120 kg/cm' (1706 lb/in.'),
and then stopping injection.
Pressure gauge
(2) After pressure rises to the above value, measure the
time it takes to drop from 100
~
90 kg/cm' (1422
~
2702
lb/in.').
100 ___. . 90 kg/cm
2
5 seconds
(1422 - 1280 lb/in.
2
)
(to drop 10 kg/cm
1
(142 lb/in.
1
))
If the pressure drops faster than this, wasli the delivery
valve, and retest. Replace ihe delivery valve if the
pressure continues to drop rapidly.
3-26
4-6 Adjusting injection volume
(uniformity of each cylinder)
The injection volume is determined
by
the fuel injection
pump rpm and rack position. Check and adjust to bring to
specified value.
4-6.1 Measuring injection volume
(1) Preparation
Set the pump rpm, rack position and measuring stroke
to the specified value and measure:
Pump RPM
1800 rpm
Pump rotating direction Right looking from drive side
Rack indicator scale
reading
7mm (0.2756 in)
Remove the rack stop bolt behind the pump and screw
in the rack fixing bolt to fix the rack.
26 (1.0236)
4 (0.1574)
_,__,,_.
4 (0.1574)
-f--1-
"3(~~
M6 x 1.0
Part Code No.
(2) Measuring injection volume
mm(in.)
1~
m-=
11.5 (0.4527)
~I
158090·51510
Measure the injection volume at the standard stroke,
and adjust as follows if it is not within the specified
value.
Measuring stroke
Specified injection volume
at standard rack position
Nonuniformity of cylinders
1,000
st
See injection pump
service data
±3o/o
4·6.2 Adjustment of injection volume
Measure the injection volume in measuring cylinders for
each cylinder, and adjust if necessary to obtain the
specified values.
(1)Push the control rack all the way to the drive side, stop
with the rack fixing bolt, and loosen the pinion/sleeve
fixing bolt 1/3 of a revolution.
Printed in Japan
AOAJ029-9002