Stihl MS 661 C-M User Manual

10 MS 661, MS 661 C-M
3.3 Chain Lubrication
In the event of trouble with the
chain lubrication system, check and
rectify other sources of faults
before disassembling the oil pump.
.
Condition Cause Remedy
Chain receives no oil Oil inlet hole in guide bar is blocked Clean oil inlet hole
Intake hose or pickup body clogged
or intake hose ruptured
Fit new intake hose and pickup
body
Valve in oil tank blocked Clean or replace valve
Teeth on worm worn Install new worm
Oil pump damaged or worn Install new oil pump
Machine losing chain oil Oil pump damaged or worn Install new oil pump
Oil suction hose connection
damaged
Install new oil suction hose
Gasket between two halves of
crankcase faulty or crankcase
cracked
Install new gasket, inspect both
halves of crankcase and replace if
necessary
Oil pump delivers insufficient oil Oil pump damaged or worn Install new oil pump
Oil pump delivery rate set too low Adjust oil pump
Worm driver is loose Install new worm
Sealing ring between oil pump and
crankcase damaged
Replace the sealing ring

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