Shibaura ST318, Workshop Manual

Page: 54 / 247

53
Disassembly and inspection
(1) Place the nozzle holder (body) in a vice and
disassemble turning the nozzle nut.
NOTE: Take care not to allow the needle valve to
drop when removing the nozzle.
(2) Wash the nozzle and needle valve and check for seizure
and sticking of the nozzle and fuel leakage on the seat
surface. Correct fuel leakage of the seat by lapping.
(3) Check the distance piece upper and lower contact areas
and correct to be sticked closely.
(4) Check the push rod for wear on the nozzle needle valve
contact surface and check the spring seat for crack.
Reassembly and adjustment
(1) When assembling a new nozzle ass’y, heat light oil to
50 - 60°C and remove the rust preventive oil in it. Slide
the body and needle valve to ensure that they slide
lightly.
(2) Invert the body, place the shim, spring, rod, piece and
nozzle on it in this order, cover the nozzle nut and
tighten.
(3) After assembly, check for the nozzle injection pressure.
1. Adjust by the adjusting washer (shim) so that the
injection is started at 11.76 MPa (120 kgf/cm
2
)
using a nozzle tester.
2. The pressure increases or decreases about 0.98 MPa
(10 kgf/cm
2
) by a washer of 0.1 mm.
(4) Injection condition
1. Small drops should not be mixed in the spray.
2. The oil should be injected describing a cone by
straight lines toward the center line of the nozzle.
3. Place white paper at about 30 cm from the nozzle
and confirm that the spray is approximately circular
when injected.
4. Keep the oil pressure lower by 1.96 MPa (20
kgf/cm
2
) than the specified value 11.76 MPa (120
kgf/cm
2
) and check that the test oil does not drop
form the nozzle end.
T151