Stihl 009 User Manual page 46

STIHL 009, 010, 011
Fault
Engine stalls at idle speed
Engine speed drops quickly under
load - low power
See also 3.2
Cause
Idle jet bores or ports clogged
Idle jet too "rich"
Idle speed screw incorrectly set –
throttle valve completely closed
Air filter plugged
Tank vent faulty
Leak in fuel line between tank and
fuel pump
Pump diaphragm damaged
Main jet bores or ports blocked
Fuel strainer dirty
Remedy
Clean jet bores and blow
out with compressed air
Turn low-speed adjustment screw
slightly clockwise (see Carburetor
Adjustment)
Set idle speed screw correctly
Clean air filter
Clean tank vent or replace if
necessary
Seal connections and replace
fuel line if necessary
Fit new pump diaphragm
Clean bores and ports
Clean fuel strainer
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