Stihl MS 251 Manual

11MS 231, MS 231 C, MS 251, MS 251 C
3.3 Chain Lubrication
In the event of trouble with the
chain lubrication system, check and
rectify other sources of faults
before disassembling the oil pump.
.
Condition Cause Remedy
Chain receives no oil Oil inlet hole in guide bar is blocked Clean oil inlet hole
Intake hose or pickup body clogged
or intake hose ruptured
Fit new intake hose and pickup
body
Valve in oil tank blocked Clean or replace valve
Teeth on worm worn Install new worm
Oil pump damaged or worn Install new oil pump
Machine losing chain oil Oil pump damaged or worn Install new oil pump
Oil suction hose connection
damaged
Install new oil intake hose
Engine housing cracked Install new engine housing
Oil pump delivers insufficient oil Oil pump damaged or worn Install new oil pump
Worm driver is loose Install new worm
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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