Stihl MS 661 C-M User Manual

7MS 661, MS 661 C-M
Fastener Thread size For component Torque
Nm
Remarks
Screw M 5x20 Spiked bumper / crankcase, bottom 8.0 5)
Collar screw M 6x50 Spiked bumper / nut (chain catcher) 6.0 5)
Screw M 5x20 Crankcase, sprocket side/fan side 10.0 4), 6)
Screw P 5x16 Bearing plug AS1 / crankcase 4.0
Screw M 5x16 Bearing plug AS2 / handlebar 6.0 4), 5)
Screw M 5x16 Bearing plug AS2 / cylinder 10.0 4), 5)
Screw P 5x16 Bearing plug ZS3 / crankcase 4.0
Screw M 5x20 Fan housing / crankcase 7.0 4), 6)
Screw M 4x12 Fan housing / winter cover plate 2.0 5)
Carrier M 13x1 L Carrier / crankshaft 70.0
Screw M 4x12 Oil pump / crankcase 3.0 4), 5)
Screw M 4x10 Ground wire cable lug / crankcase 2.5 4), 5)
Screw P 4x10 M-Tronic cable lug / handle housing 1.5
Screw P 4x10 Heater cable lug / handle housing 1.5 V, W
Screw M 5x20 Muffler / crankcase 10.0 4), 5), 6)
Screw M 5x30 Muffler / cylinder 10.0 3), 4), 6)
Screw M 5x6 Muffler casing, top 6.0 4), 5)
Screw M 4x12 Switch unit / carburetor 2.0 5)
Screw P 4x10 Guard / handle housing 1.5
Nut M 10x1 Flywheel / crankshaft 45.0 7)
Screw M 4x8 Side plate / crankcase 2.0 4)
Screw M 3x20 Manifold clamp / cylinder 0.5
Screw M 4x20 Ignition module / control unit / crankcase 4.0 5)
Stud M 5 Stud / cylinder 8.0 5)
Screw 6-32
UNCx11.5
Thermostatic switch / carburetor cover 1.1 V
Screw M 3x4.5 Solenoid valve / carburetor 0.7
Collar nut M 5 Carburetor 3.5
Screw P 6x40 Elbow connector / handle housing 6.0
Screw M 5x16 Elbow connector / handlebar 7.0 4), 6)
M 14x1.25 Spark plug 25.0
Screw M 6x30 Cylinder / crankcase 15.0 4), 6)
Remarks:
1) Loctite 242 or 243, medium strength
2) Loctite 270, high strength
3) Loctite 272, high strength up to 250°C
4) Screws with binding head
5) Micro-encapsulated screws
6) Waxed screws
7) Degrease crankshaft / flywheel and mount oil-free
W) Heated handles
V) Carburetor heating

Stihl MS 661 C-M Specifications

General

Idle speed	- RPM
Motor type	2-stroke motor
Chain pitch	3/8 \
Blade length	800 mm
Product color	Black, Grey, Orange
Automatic oiling	Yes
Engine displacement	91.1 cm³
Power source	Gasoline
Sound power level	118 dB
Vibration emission	6.9 m/s²
Sound pressure level	105 dB

Weight and Dimensions

Weight	7400 g