Stihl MS 191 User Manual

13MS 311, MS 391
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 Replace the 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 a new metering diaphragm
Metered diaphragm deformed Fit a new metering diaphragm
Poor acceleration Setting of low speed screw too lean Check basic carburetor setting,
correct if necessary
Setting of high speed screw too
lean
Check basic carburetor setting,
correct if necessary
Inlet needle sticking to valve seat Remove inlet needle, clean and
refit
Diaphragm gasket leaking Fit new diaphragm gasket
Metering diaphragm damaged or
shrunk
Fit a new metering diaphragm
Tank vent faulty Replace tank vent
Leak on fuel hose from tank to
carburetor
Seal connections or install new fuel
hose

Stihl MS 191 Specifications

General

Brand	Stihl
Model	MS 191
Category	Chainsaw
Language	English