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STIHL 029, 039
13
Condition
Cause Remedy
Engine stalls at idle speed
Idle jet bores or ports
Clean jet bores and ports
blocked
with compressed air
Idle jet "too rich"
Screw down low speed adjusting
screw slightly
(see Carburetor Adjustment)
Setting of idle speed
Set idle speed adjusting
adjusting screw incorrect
screw correctly
- throttle shutter completely
closed
Small plastic plate in valve
Clean or renew valve jet
jet does not close
Engine speed drops quickly under
Air filter plugged
Clean air filter
load - low power
Tank vent faulty
Clean or replace tank vent
if necessary
Leak in fuel line between tank
Seal or renew connections
and fuel pump
and fuel line
Pump diaphragm damaged or
Fit new pump diaphragm
fatigued
Main jet bores or ports
Clean bores and ports
blocked
Fuel pickup body dirty
Clean pickup body, fit new
filter
Fuel strainers dirty
Clean fuel strainers