Stihl MS 661 C-M Instruction Manual

0458-759-8221-C
59
English 23 Troubleshooting Guide
23.1 Chain saw
23 Troubleshooting Guide
Many performance issues can be resolved with a few simple steps. When troubleshooting, STIHL recommends that you start
with the following measures:
► Clean the air filter, @ 21.3.
► Clean or replace the spark plug, @ 21.4.
► As appropriate for conditions, set the saw's "shutter" for winter or summer operation, @ 17.3 or @ 17.4.
► If these measures do not resolve the issue, continue to the steps described below.
Always shut off the engine before carrying out any inspection, cleaning or maintenance.
Condition Possible Cause Remedy
The engine does not start. There is insufficient fuel in the fuel tank. ► Refuel the chain saw, @ 13.2.
The engine is flooded. ► Clear the combustion chamber, @ 23.2.
The carburetor is iced up. ► Allow the engine to warm up gradually to a
temperature of about 50 °F (10 °C).
The engine idles
erratically.
The carburetor is iced up. ► Allow the engine to warm up gradually to a
temperature of about 50 °F (10 °C).
The engine stops while
idling.
The carburetor is iced up. ► Allow the engine to warm up gradually to a
temperature of about 50 °F (10 °C).
Acceleration is poor. The chain is tensioned too tight. ► Properly tension the chain, @ 10.3.
Insufficient bar and chain oil. ► Increase oil feed rate, @ 11.3.
The engine does not reach
maximum speed.
The chain saw is not properly calibrated to the
ambient conditions.
► Calibrate the chain saw, @ 17.2.
The chain does not rotate
when throttle is opened.
The chain brake is engaged. ► Disengage the chain brake, @ 12.2.
The chain is tensioned too tight. ► Properly tension the chain, @ 10.3.
The guide bar sprocket is blocked. ► Spray the guide bar sprocket with resin
remover.
During sawing, the wood
smokes or smells burnt.
The chain is dull or improperly sharpened. ► Properly sharpen the chain, @ 10.3.
Working technique is improper or the saw is
being mis-used.
► Obtain instruction on proper working
technique.
Insufficient bar and chain oil. ► Have the chain lubrication mechanism
checked by an authorized STIHL servicing
dealer.

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