Stihl MS 251 Manual

86 MS 231, MS 231 C, MS 251, MS 251 C
: Pull the fuel hose (1) and fuel
return hose (2) out of the air
guide shroud.
– Remove the air guide shroud.
: Remove the fuel pump (1) with
the fuel hoses and elbow
connector (2), inspect and
replace if necessary, b 12.11.4
– Pull out the shutter , check it and
replace if necessary.
Installing
– Remove the grommet, check and
replace if necessary.
2310RA339 TG
2
1
2310RA340 TG
1
2
2310RA341 TG
1
– Coat outside of grommet with
STIHL press fluid to simplify
installation, b 14
: Fit the grommet (1) in the
hole (arrow) and make sure it is
properly seated.
– Install fuel pump with fuel hoses
and elbow connector, b 12.11.4
: To fit the manifold (2) through the
air guide shroud's opening, wind
a piece of string (1) (about 15 cm
long) around the back of manifold
flange.
2310RA324 TG
1
2310RA325 TG
2
1
– Coat manifold flange with STIHL
press fluid to simplify installation,
b 14
: Place the air guide shroud (1) in
position.
: Push the new fuel hose (2)
through the bore (arrow).
– Use STIHL press fluid to simplify
assembly, b 14
: Push the new fuel hose (3)
through the grommet (4).
2310RA342 TG
3
12
4
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Stihl MS 251 Specifications

General

Idle speed	2800 RPM
Motor type	2-stroke motor
Chain pitch	1/308 \
Blade length	450 mm
Product color	Black, Grey, Orange
Motor speed (max)	10000 RPM
Oil tank capacity	0.2 L
Fuel tank capacity	0.39 L
Engine displacement	45.6 cm³
Kickback protection	Yes
Engine power	3 hp
Power source	Gasoline
Sound power level	114 dB
Vibration emission	3.9 m/s²
Sound pressure level	103 dB

Weight and Dimensions

Weight	4900 g