Stihl MS 201 Manual page 16

Condition
Engine will not idle, idle speed too
high
Engine stops while idling
Saw chain rotates at idle speed
Power tool smells of fuel or loses
fuel
MS 201, MS 201 C, MS 201 T, MS 201 TC
Cause
Throttle shutter opened too wide by
idle speed screw (LA)
Oil seals/crankcase leaking
Throttle shutter does not close
Idle jet bores
or ports blocked
Setting of low speed screw (L) too
rich or too lean
Setting of idle speed screw LA
incorrect – throttle shutter
completely closed
Tank vent faulty
Leak in fuel hose from tank to
carburetor
Engine idle speed too high
Clutch springs stretched or fatigued Replace the clutch springs or install
Clutch spring hooks broken
Fuel hoses leaking or damaged
Fuel tank damaged
Pump diaphragm, metering
diaphragm or diaphragm gasket
faulty
Remedy
Reset idle speed screw (LA)
correctly
Seal oil seals / crankcase, replace if
necessary
Install new carburetor
Clean the carburetor
Reset low speed screw (L) correctly
Reset idle speed screw (LA)
correctly
Fit new tank vent
Seal connections or install new fuel
hose
Readjust with idle speed screw
LA (counterclockwise)
new clutch
Replace the clutch springs
Check fuel hoses, push fully onto
connectors or replace if necessary
Install new fuel tank
Replace pump diaphragm,
metering diaphragm or diaphragm
gasket
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