Operation Manual

MS 251, MS 251 C
English
58
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
Engine
STIHL single cylinder two-stroke engine
MS 251, MS 251 C
Ignition System
Electronic magneto ignition
Fuel System
All position diaphragm carburetor with
integral fuel pump
Chain Lubrication
Fully automatic, speed-controlled oil
pump with rotary piston
Weight
Cutting Attachment
Recommended cutting attachments
complying with Section 5.11 of ANSI B
175.1-2000.
Observe notes on ANSI B 175.1-2000
and definition of "low kickback chain" in
chapter on "Safety Precautions and
Working Techniques".
Rollomatic E 3/8" P guide bars
Rollomatic E .325" guide bars
3/8" P chain
.325" saw chains
Specifications
A = 300 hours
B = 125 hours
C = 50 hours
Displacement: 2.78 cu.in
(45.6 cm
3
)
Bore: 1.73 in (44 mm)
Stroke: 1.18 in (30 mm)
Engine power to
ISO 7293:
3.0 hp (2.2 kW) at
9,500 rpm
Idle speed: 2,800 rpm
High speed setting
when performing
repairs (with bar and
chain): 13,000 rpm
Spark plug (resistor
type): NGK CMR6H
Electrode gap: 0.02 in (0.5 mm)
Fuel tank capacity: 13.2 fl.oz (0.39 L)
Oil tank capacity: 6.7 fl.oz (0.2 L)
dry, without bar and chain
MS 251 11.0 lbs
(4.9 kg)
MS 251 C with quick chain
adjuster and
Easy2Start:
11.5 lbs
(5.2 kg)
Reduced kickback STIHL guide bar
(with green label)
Cutting lengths: 12, 14, 16, 18 in
(30, 35, 40, 45 cm)
Pitch: 3/8" P (9.32 mm)
Groove width: 0.050 in (1.3 mm)
Nose sprocket: 9-tooth
Reduced kickback STIHL guide bar
(with green label)
Cutting lengths: 14, 16, 18 in (35,
40, 45 cm)
Pitch: .325" (8.25 mm)
Groove width: 0.063 in (1.6 mm)
Nose sprocket: 11-tooth
Low kickback STIHL saw chains (with
green label)
Picco Micro 3 (63 PM3) Type 3636
Picco Super 3 (63 PS3) Type 3616
Picco Duro (63 PD3) Type 3612
Pitch: 3/8" P (9.32 mm)
Drive link gauge: 0.050 in (1.3 mm)
Low kickback STIHL saw chains (with
green label)
Rapid Micro 3 (26 RM3) Type 3634
Rapid Duro 3 (26 RD3) Type 3667
Pitch: .325" (8.25 mm)
Drive link gauge: 0.063 in (1.6 mm)