Yanmar 3JH3E - 6-5 Adjusting fuel injection nozzle

Chapter 3 Fuel Injection Equipment
_6_. F_u_el_I_n_je_c_t_io_n_N_oz_z_l_e ________________________ 3,4JH3(B)(C)E
6-5 Adjusting fuel injection nozzle
6-5.1 Adjusting opening pressure
Mount the fuel injection nozzle on the nozzle tester and
use the handle to measure injection starting pressure
1f it
is not
at the specified pressure. use the adjusting shims to
increase/decrease pressure (both hole and pintle types).
Injection starting pressure
kg/cm'
Injection starting pressure I
195~205
6-5.2 Injection test
After adjusting the nozzle to the specified starting pres-
sure, check the fuel spray condition and seat
oil tightness.
(1) Check seat oil tightness
After two or three injections, gradually increase the
pressure up to 20 kg/cm
2
(284 lb/in
2
)
before reading the
starting pressure, maintain the pressure for 5 seconds,
and make sure that
no oil is dripping from the tip of the
nozzle.
Test the injection with a nozzle tester; retighten and
test again
if there is excessive oil leakage from the
overflow coupling.
Replace the nozzle
as a sat if oil leakage is still ex-
cessive.
(2) Injection spray condition
Operate the nozzle tester lever once to twice a second
and check for abnormal injection.
1) Hole type nozzles
Replace hole type nozzles that do not satisfy the fol-
lowing conditions:
• Proper spray angle (
8)
• Correct injection angle (a)
• Complete atomization of fuel
• Prompt starting/stopping of injection
Printed in Japan
HINSHl-H80O9
Correct
Poor
3-35
a
Spray from each nozzle
hole is uniform
• Excessive difference
in apray angle( fJ)
• Excessive difference
in injection angle (er)
• Incomplete atomization
• Sluggish starting/stopping
of injection