Stihl GS 461

78 GS 461
10.7 Tank vent
10.7.1 Testing
If problems develop in the
carburetor or fuel supply, the tank
vent must always also be tested and
replaced if necessary. Correct
functioning is determined by testing
the fuel tank with negative pressure
or gauge pressure via the fuel
suction hose.
– Open filler cap and drain fuel
tank, b 1
– Close the filler cap
– Remove the carburetor, b 10.3
Testing with negative pressure
: Push the connector (1)
0000 855 9200 with hose (2) into
the fuel suction hose
: Slide ring (3) to the left and
connect the pump (4)
0000 850 1300 to the hose (2)
– Create vacuum in fuel tank
Pressure is equalized via the tank
vent. A negative pressure must not
build up inside the tank.
– Clean the area around the tank
vent
– Replace the tank vent or tank
housing if necessary, b 10.7 or
b 10.8.3
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3
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Testing with gauge pressure
: Slide ring (1) to the right and
connect the pump (2)
0000 850 1300 to the double
connector (arrow) – create
excess pressure in fuel tank
– Actuate the pump until the
pressure gauge shows a
pressure of 0.5 bar. If this
pressure remains constant for at
least 20 seconds, the tank and
tank vent are airtight. If the
pressure drops, the leak must be
located and the faulty part
replaced.
– Reassemble parts in reverse
order
10.7.2 Removal and installation
– Remove the air filter cover,
b 10.1
: Pull the hose (1) off the
connector (arrow) on the tank
vent
2
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: Check hose (1), remove if
necessary from connector of filter
base and replace
: Push new hose (1) onto
connector of filter base
: Pry out the tank vent (1) via the
mounting rib (arrow) – always
use new tank vent
Installation
– Wet O-ring of new tank vent with
STIHL press fluid, b 12
– Press new tank vent in by hand
until you hear it click into place
and push hose onto connector of
tank vent
– Reassemble remaining parts in
reverse order
1
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