Stihl SR 420 Instruction Manual page 19

Metering knob
2
4
3
The discharge rate can be infinitely
N
varied by turning the metering
knob (2) on the nozzle (3).
Position 1 = minimum flow rate
Position 6 = maximum flow rate
The numbers on the metering knob must
be lined up with the lug (4) under the
knob.
Discharge rate without pressure pump
Spray tube 0° to - 30° to the horizontal
Knob position Discharge rate (l/min)
(mean value)
1 0.12
2 0.44
3 0.86
4 1.27
5 1.58
6 1.81
Discharge rate without pressure pump,
with ULV nozzle
Spray tube 0° to - 30° to the horizontal
SR 420
Knob position Discharge rate (l/min)
(mean value)
0.5 0.03
0.65 0.07
0.8 0.10
Discharge rate with pressure pump
(special accessory)
Spray tube horizontal (0°)
Knob position Discharge rate (l/min)
(mean value)
1.0 0.64
1.6 1.88
2.0 3.13
Discharge rate with pressure pump
(special accessory), with ULV nozzle
Spray tube horizontal (0°)
Knob position Discharge rate (l/min)
(mean value)
0.5 0.10
0.65 0.20
0.8 0.42
Checking metering unit
Place the machine on the ground.
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Remove the baffle screen and
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pressure pump.
Fill the container with water up to 10
N
liter mark.
Set the metering knob to position 6.
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Start the machine.
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Hold the spray tube horizontally, run
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the engine at full throttle, spray the
contents of the container down to
the 5 liter mark and note the time
taken.
The time required to spray 5 liters fluid
should be between 140 and 170
seconds.
In case of deviations:
Check the metering unit for
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contamination and clean it if
necessary.
Check engine setting and correct if
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necessary.
If there is no improvement, contact your
dealer for assistance.
English
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