Instruction Manual

MS 311, MS 391
English
45
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 (breakerless) magneto
ignition
This spark ignition system meets all
requirements of the Canadian
Interference-Causing Equipment
Standard CAN ICES-2/NMB-2.
Fuel System
All position diaphragm carburetor with
integral fuel pump
Chain lubrication
Fully automatic, speed-controlled oil
pump with rotary piston. Additional
manual oil flow control
Weight
Cutting Attachment
The actual cutting length can be less
than the specified cutting length.
STIHL cutting attachments complying
with CSA Standard Z 62.3:
Rollomatic E guide bars
3/8" chains
Chain Sprockets
Other cutting attachments
Other cutting attachments complying
with CSA Standard Z 62.3 are available:
see section CSA Standard Z 62.3, the
"Chain Leaflet" inside the chain box or
contact your local STIHL dealer.
Specifications
A = 300 hours
B = 125 hours
C = 50 hours
Displacement: 59.0 cc
Bore: 47 mm
Stroke: 34 mm
Engine power to
ISO 7293:
3.1 kW (4.2 bhp)
at 9,500 rpm
Idle speed: 2,800 rpm
Max. permissible
speed (with cutting
attachment): 13,000 rpm
Displacement: 64.1 cc
Bore: 49 mm
Stroke: 34 mm
Engine power to
ISO 7293:
3.3 kW (4.5 bhp)
at 9,500 rpm
Idle speed: 2,800 rpm
Max. permissible
speed (with cutting
attachment): 13,000 rpm
Spark plug (resistor
type):
NGK BPMR 7 A,
Bosch WSR 6 F
Electrode gap: 0.5 mm
Fuel tank capacity: 600 cc (0.6 l)
Oil tank capacity: 350 cc (0.35 l)
dry, without bar and chain
MS 311: 6.2 kg
MS 391: 6.2 kg
Cutting lengths: 40, 45, 50 cm
Pitch: 3/8" (9.32 mm)
Groove width: 1.3 mm or 1.6 mm
Nose sprocket: 10
-
tooth
Rapid Micro (33 RM) Type 3650
Rapid Micro 3 (33 RM3) Type 3662
Rapid Super (33 RS) Type 3623
Rapid Super 3 (33 RS3) Type 3624
Pitch: 3/8" (9.32 mm)
Drive link gauge: 1.3 mm
Rapid Micro (36 RM) Type 3652
Rapid Micro 3 (36 RM3) Type 3664
Rapid Super (36 RS) Type 3621
Rapid Super 3 (36 RS3) Type 3626
Pitch: 3/8" (9.32 mm)
Drive link gauge: 1.6 mm
7
-
tooth for 3/8" (rim sprocket)