Checking And Changing Pressure Valve; Adjusting Idling Speed - Sisu Diesel 320 Workshop Manual

J. Checking and changing pressure
valve
1. Clean the injection pump, injectors and surrounding parts.
Disconnect the delivery pipes.
9052 47800
2. Connect the pressure gauge 9052 47800 to the pressure
valve holder which is to be checked.
3. Rotate the engine with the starter motor, until the gauge re-
ading is about 330 bar.
Note! Pressure rises fast, do not damage the gauge. Get
ready to pull the stop control out as soon as the gauge reading
reaches an adequate pressure value.
4. Let the gauge reading lower at first about 30 bar. When the
gauge shows 300 bar, observe the reading during one min-
ute. During this time the gauge reading must not lower too
much (max 30...50 bar). If the pressure lowers faster than
specified, the pressure valve must be cleaned or replaced.
Note! The pressure valve plunger and guide should always
be replaced in pairs.
5. Open the pressure valve holder locking and holder. Re-
move the valve spring, plunger and the guide.
6. Rinse the plunger and guide in clean fuel or test liquid and
at the same time rotate the plunger in its guide and press the
sealing surfaces against each other.
7. Fit the pressure valve into the fuel injection pump. Place the
spring in place and tighten the holder.
Fuel System
Note! Replace the sealing ring and o---ring.
8. Tighten the holder as follows:
--- Tighten first to 30 Nm.
--- Open the holder about ½ a turn and tighten to 40 Nm.
--- Open the holder about ½ a turn and tighten to 45 Nm.
K. Adjusting idling speed
If the idling speed of the engine deviates from the value given
in the specifications or if the engine revs vary at the idling
speed, adjust the idling speed as follows:
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1. Unscrew the idling speed adjusting nut cap (1) and the cap
(2) on the idling speed additional spring adjusting screw.
2. Ensure that the throttle lever is in the idling position and that
the engine is at normal operating temperature.
3. Start the engine and loosen the adjusting screw of the addi-
tional spring so that it does not affect the idling speed.
4. Adjust the idling speed using the adjusting screw to about
20...30 rpm below rated speed and lock the adjusting screw.
5. Run the engine a few times and ensure that the idling speed
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remains as set.
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1
2
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