MS 661 C-M
English
40
If groove depth is less than specified:
N Replace the guide bar.
The drive link tangs will otherwise
scrape along the bottom of the groove –
the cutters and tie straps will not ride on
the bar rails.
N Turn the knob above the rear handle
in the direction of the arrow and
remove the carburetor box cover
N Remover filter
If there is a noticeable loss of engine
power:
N Knock out the filter or blow it clear
with compressed air from the inside
outwards
If knocking-out or blowing-out does not
suffice, or in the case of stubborn dirt or
stuck filter fabric, the filter must be
subjected to a thorough cleaning.
Always replace a damaged filter.
Thorough filter cleaning
N Wash the filter in STIHL special-
purpose cleaner (special
accessory) or a clean, non-
flammable cleaning liquid (e.g.,
warm soapy water) – rinse the filter
from inside to out under a water jet
– do not use high-pressure cleaners
N Dry all filter parts – do not expose to
extreme heat
N Do not oil the filter
N Reinstall filter
Chain
type
Chain pitch Minimum
groove depth
Picco 1/4" P 0.16" (4.0 mm)
Rapid 1/4" 0.16" (4.0 mm)
Picco 3/8" P 0.20" (5.0 mm)
Rapid 3/8"; 0.325" 0.24" (6.0 mm)
Rapid 0.404" 0.28" (7.0 mm)
Remove air filter
1166BA011 AM1166BA012 AM
Cleaning the Air Filter