Stihl MS 441 Manual page 18

Condition
Engine speed drops quickly
under load – low power
Engine runs extremely richly, no
power and very low final speed
Engine too rich, loss of power and
final speed too low
Erratic idling, too lean
MS 441, MS 441 C
Cause
Air filter dirty
Throttle shutter does not open fully
Tank vent faulty
Fuel pick-up body dirty
Fuel strainer dirty
Leak in fuel line from tank to fuel
pump
Setting of high speed screw H too
rich
Main jet bores or ports blocked
Pump diaphragm damaged or
fatigued
Impulse hose damaged or kinked
Air flap does not open
Air flap does not open fully at full
throttle
Air flap does not close completely
Remedy
Clean air filter, replace if necessary
Check throttle cable and rod
Fit new tank vent
Install a new pick-up body
Clean fuel strainer in carburetor,
replace if necessary
Seal connections, replace line if
necessary
Check basic carburetor setting,
adjust if necessary
Clean carburetor
Fit a new pump diaphragm
Fit a new impulse hose
Check carburetor; install a new
carburetor if necessary
Check carburetor; install a new
carburetor if necessary
Check carburetor; install a new
carburetor if necessary
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