Specifications - Stihl MS 251 Instruction Manual

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Specifications

EPA / CEPA
The Emission Compliance Period
referred to on the Emissions
Compliance Label indicates the number
of operating hours for which the engine
has been shown to meet Federal
emission requirements.
Category
A = 300 hours
B = 125 hours
C = 50 hours
Engine
STIHL single cylinder two-stroke engine
MS 251, MS 251 C
Displacement: 2.78 cu. in. (45.6
3
cm )
Cylinder bore: 1.73 in. (44 mm)
Piston stroke: 1.18 in. (30 mm)
Engine power
according to 3.0 hp (2.2 kW) at
ISO 7293: 10,000 rpm
Idling speed: 2,800 rpm
Maximum permissi-
ble speed with
cutting attachment: 13,000 rpm
Ignition system
Electronic magneto ignition
56
Spark plug
(suppressed): NGK CMR6H
Electrode gap: 0.02 in. (0.5 mm)
Fuel system
All position diaphragm carburetor with
integral fuel pump
Fuel tank capacity: 13.2 fl.oz (0.39 l)
Chain lubrication
Fully automatic, speed-controlled oil
pump with rotary piston
Oil tank capacity: 6.7 fl.oz (0.2 l)
Weight
Dry, without cutting attachment
MS 251
MS 251 C with quick chain
tensioner and
Easy2Start:
Cutting Attachments
Recommended cutting attachments
conforming with the 45 degree
computed kickback angle requirement
of Section 5.11 of
ANSI/OPEI B175.1-2012 when used on
this model chain saw (see the chapter
on "Safety Precautions and Working
Techniques"):
Rollomatic E guide bars
Reduced kickback STIHL guide bars
(with green label)
Bar lengths:
Pitch:
Groove width: 1.3 mm (0.050 in)
Sprocket nose: 9-tooth
Reduced kickback STIHL guide bars
(with green label)
Bar lengths:
Pitch:
Groove width: 1.6 mm (0.063 in)
Sprocket nose: 11-tooth
Actual cutting length will be less than
listed bar length.
Saw chain 3/8" P
Low kickback STIHL saw chain (with
11.0 lbs.
green label)
(4.9 kg)
Picco Micro 3 (63 PM3) Type 3636
Picco Super 3 (63 PS3) Type 3616
11.5 lbs.
Picco Duro (63 PD3) Type 3612
(5.2 kg)
Pitch:
Drive link gauge:
Saw chain .325"
Low kickback STIHL saw chain (with
green label)
Rapid Micro 3 (26 RM3) Type 3634
Rapid Duro 3 (26 RD3) Type 3667
Pitch:
Drive link gauge:
30, 35, 40, 45 cm (12,
14, 16, 18 in.)
3/8" P (9.32 mm)
35, 40, 45 cm (14, 16,
18 in.)
.325" (8.25 mm)
3/8" P(9.32 mm)
1.3 mm (0.050 in)
.325" (8.25 mm)
0.063 in. (1.6 mm)
MS 251, MS 251 C