Stihl MS 251 Manual

49MS 231, MS 231 C, MS 251, MS 251 C
: Make sure the leg spring (arrow)
locates properly inside the spark
plug boot.
– Fit the spark plug boot and push
the ignition lead fully into the
guide, b 7.3
Ignition lead and spark plug boot
must not touch the air guide shroud.
– Reassemble all other parts in the
reverse sequence.
7.6 Flywheel
– Remove the fan housing, b 8.2
– Use locking strip to block the
piston, b 4.2
: Unscrew the flywheel nut (1).
2310RA129 TG
2310RA422 TG
1
: Screw the puller (1)
5910 893 0801 onto the
crankshaft as far as stop, then
back it off a 1/4 turn.
: Tap the puller (1) sharply to
release the flywheel (2) from its
tapered seat.
Take care not to damage the pawls
on models with ErgoStart.
: Take the puller (1)
5910 893 4504 off the crankshaft
and remove the flywheel.
The flywheel and magnet
poles (arrows) must not be
damaged or have turned blue.
Replace flywheel if necessary.
2310RA097 TG
1
2
0001RA167 TG
– On models with ErgoStart, check
the pawls for damage and
freedom of movement, b 8.4.
Installing
The flywheel and crankshaft stub
must be free from grease before
assembly.
Make sure the key (arrow) engages
the slot in the crankshaft.
– Set the air gap between the
ignition module and flywheel,
b 7.3
– Reassemble all other parts in the
reverse sequence.
2310RA110 TG
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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