Stihl MS 661 C-M User Manual

13MS 661, MS 661 C-M
3.6 Carburetor
Condition Cause Remedy
Carburetor floods; engine stalls Inlet needle not sealing
– foreign matter in valve seat or
cone
Remove and clean the inlet needle,
clean the carburetor
Inlet needle worn Fit new inlet needle
Inlet control lever sticking on
spindle
Check the inlet control lever and
replace if necessary
Helical spring not located on nipple
of inlet control lever
Remove the inlet control lever and
refit it correctly
Perforated disc on diaphragm is
deformed and presses constantly
against the inlet control lever
Fit new metering diaphragm
Metered diaphragm deformed Fit new metering diaphragm
Poor acceleration Low speed screw L and / or high
speed screw H too lean
Check basic carburetor setting,
correct if necessary
Models with M-Tronic, carburetor
setting too lean
Check M-Tronic with STIHL MDG 1
and troubleshooting chart, b 8.7,
adjust or calibrate control unit,
b 8.1
Inlet needle sticking to valve seat Remove inlet needle, clean and
refit
Metering diaphragm or gasket
damaged
Fit a new metering diaphragm and
gasket
Tank vent faulty Fit new tank vent
Leak in fuel hose between pickup
body and carburetor
Seal connections or install new fuel
hose

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