Tank Vent; 13.10.1 Testing; Removing And 16. Installing - Stihl MS 661 Manual

1
: Install the tank housing, pushing
the impulse hose (1) onto the
stub (arrow) at the same time,
b 13.11.4
– Install the carburetor, b 13.4
– Reassemble all other parts in the
reverse sequence.
13.10

Tank Vent

13.10.1 Testing

If problems occur on the carburetor
or the fuel supply system, also
check and clean the tank vent and
replace it if necessary. Check
function by performing pressure and
vacuum tests on the tank via the fuel
suction hose.
– Open the fuel tank cap and drain
the fuel tank, b 1.1.
– Close the tank cap.
– Remove the carburetor, b 13.4
– Remove the retainer with switch
shaft and put it to one side,
b 11.1.1
MS 661, MS 661 C-M
Vacuum test
2
1
3
: Push nipple (1) 0000 855 9200
with hose (2) into the fuel suction
hose.
: Push the ring (3) to the left and
connect the pump (4)
0000 850 1300 to the hose (2)
– create a vacuum in the fuel
tank.
Equalization of pressure takes
place via the tank vent. There must
be no buildup of vacuum in the tank.
– Clean the area around the tank
vent.
– If necessary, install a new tank
vent or tank housing, b 13.10 or
b 13.11.4
Pressure test
4
: Push ring (1) to the right
– pressurize the fuel tank.
– Operate the pump until the
pressure gauge indicates a
pressure of 0.5 bar. If this
pressure remains constant for at
least 20 seconds, the tank,
including the tank vent, is airtight.
If the pressure drops, the leak
must be located and the faulty
part replaced.
– Remove the nipple and pump.
– Reassemble in the reverse
sequence.
13.10.2 Removing and Installing
– Remove the filter cover
2
: Pry the tank vent (1) out of its
seat using the rib (2) for leverage.
– Always install a new tank vent.
1
1
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