Stihl MS 311, Manual, Page: 85 / 94

84 MS 311, MS 391
Pressure test
: Push the ring (1) to the right and
connect the pump (2)
0000 850 1300 to the
nipple (arrow)
– 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 fuel tank,
including the tank vent, is airtight.
If the pressure drops, the leak
must be located and the faulty
part replaced.
– Always install a new fuel hose.
– Reassemble in the reverse
sequence.
12.10.2 Removing and Installing
: Take out the screws (arrows) and
pry the AV spring (1) out of the
handlebar.
0001RA408 TG
1
2
4903RA243 TG
1
: Take out the screw (1).
: Lower the tank housing (2).
: Slide the wooden assembly
block (1) between the engine
housing and tank housing.
: Pry the tank vent (1) out of its
seat using the rib (arrow) for
leverage.
Always install a new tank vent.
4903RA060 TG
1
2
4903RA108 TG
1
1
4903RA244 TG
– Coat sealing ring of new tank
vent with STIHL press fluid,
b 14
– Push home the tank vent by hand
until it snaps into position.
– Reassemble all other parts in the
reverse sequence.
12.11 Fuel Intake
12.11.1 Pickup Body
Any impurities mixed with the fuel
are retained by the pickup body
(filter). The fine pores of the filter
eventually become clogged with
minute particles of dirt. This restricts
the passage of fuel and results in
fuel starvation.
In the event of problems with the
fuel supply system, always check
the fuel tank and the pickup body
first.
– Troubleshooting, b 3.6 or
b 3.7
Clean the fuel tank if necessary,
– Open the tank cap and drain the
fuel tank.
– Pour a small amount of clean
gasoline into the fuel tank. Close
the tank and shake the saw
vigorously.
– Open the tank again and drain it.
– Dispose of fuel properly in
accordance with environmental
requirements,
b 1