Stihl MS 181 User Manual

92 MS 171, MS 181, MS 211
14.8 Tank Vent
14.8.1 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
hose.
– Open the tank cap and drain the
fuel tank. Dispose of fuel
properly, b 1.
– Close the tank cap.
– Remove the carburetor, b 14.3
– Pull off the fuel hose and elbow
connector, b 14.9.2
: Push the nipple (1)
0000 855 9200 into the fuel hose
(arrow).
533RA400 TG
1
Machines with Manual Fuel Pump
– Remove the manual fuel pump,
b 14.8.3
– Pull the fuel hose (1) out of the
guides.
– Disconnect the fuel hose from the
fuel pump (1).
: Seal the fuel hose (1) with a plug
(arrow).
Vacuum test
: Push the ring (1) to the left and
connect the pump (2)
0000 850 1300 to the nipple
(arrow)
– subject the fuel tank to a
vacuum.
Equalization of pressure takes
place via the tank vent. There must
be no build-up of vacuum in the
tank.
533RA262 TG
1
533RA401 TG
1
2
– Clean the area around the tank
vent.
– If necessary, replace the tank
vent or the tank, b 14.8
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 tank,
including the tank vent, is airtight.
If it drops, the leak must be found
and the defective part replaced.
– Reassemble in the reverse
sequence.
533RA402 TG
1
2
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Stihl MS 181 Specifications

General

Idle speed	- RPM
Motor type	2-stroke motor
Chain pitch	3/8 \
Blade length	400 mm
Product color	Black, Grey, Orange
Chain tensioner	Yes
Motor speed (max)	10000 RPM
Fuel tank capacity	0.266 L
Engine displacement	31.8 cm³
Power source	Gasoline
Sound power level	112 dB
Vibration emission	3.5 m/s²
Sound pressure level	100 dB

Weight and Dimensions

Weight	43004300 g