Stihl MS 311 User Manual

MS 311, MS 391
English
51
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 311
MS 391
Ignition system
Electronic magneto ignition
Fuel system
All position diaphragm carburetor with
integral fuel pump
Chain lubrication
Fully automatic, speed-controlled oil
pump with reciprocating piston –
additional manual oil flow control
Weight
Cutting attachment
Recommended cutting attachments in
compliance with Sec. 5.11 of ANSI
standard B 175.1-2000
Observe the information about ANSI
standard B 175.1-2000 as well as the
definition "low-kickback saw chain" in
the section "Safety Precautions and
Working Techniques".
Rollomatic E guide bars
Saw chains 3/8"
Specifications
A = 300 hours
B = 125 hours
C = 50 hours
Displacement: 3.60 cu. in.
(59.0 cm
3)
Bore: 1.85in. (47mm)
Stroke: 1.34in. (34mm)
Engine power to
ISO 7293:
4.2 hp (3.1 kW)
at 9500 rpm
Idle speed: 2800 rpm
Maximum permissible
speed with bar and
chain: 13000 rpm
Displacement: 3.90 cu. in.
(64.1 cm
3
)
Bore: 1.93 in. (49 mm)
Stroke: 1.34in. (34mm)
Engine power to
ISO 7293:
4.4 hp (3.3 kW)
at 9500 rpm
Idle speed: 2800 rpm
Maximum permissible
speed with bar and
chain: 13000 rpm
Spark plug
(suppressed):
NGK BPMR 7 A,
Bosch WSR 6 F
Electrode gap: 0.02 in. (0.5 mm)
Fuel tank capacity: 20.3 oz (0.60 l)
Oil tank capacity: 11.8 oz (0.350 l)
dry, without bar and chain
MS 311: 14.1 lbs. (6.4 kg)
MS 391: 14.1 lbs. (6.4 kg)
STIHL reduced kickback guide bars
(with green label)
Bar lengths: 16, 18, 20 in. (40, 45,
50 cm)
Pitch: 3/8" (9.32 mm)
Groove width: 0.050 in. (1.3 mm) or
0.063 in. (1.6 mm)
Sprocket nose: 10- or 11-tooth
STIHL reduced kickback saw chains
(with green label)
Rapid Micro Comfort 3 (33 RMC3)
Rapid Micro Comfort 3 (36 RMC3)
Rapid Super Comfort 3 (33 RSC3)
Rapid Super Comfort 3 (36 RSC3)
Pitch: 3/8" (9.32 mm)
Drive link gauge: 0.050 in. (1.3 mm) or
0.063 in. (1.6 mm)

Stihl MS 311 Specifications

General

Oil tank capacity	0.348 L
Fuel tank capacity	0.6 L
Power source	Gasoline

Weight and Dimensions

Weight	6200 g