16
MS 780, MS 880
Condition
Cause
Remedy
Engine will not idle, idle speed too
high
Throttle shutter opened too wide by
idle speed screw
LA
Reset idle speed screw
LA
correctly
Oil seals/crankcase leaking
Seal or replace oil seals/crankcase
Engine stalls at idle speed
Idle jet bores
or ports blocked
Clean the carburetor
Low speed screw too rich or
too lean
Reset low speed screw
L
correctly
Setting of idle speed screw
LA
incorrect – throttle shutter
completely closed
Reset idle speed screw
LA
correctly
Tank vent faulty
Replace tank vent
Leak on fuel hose from tank to
carburetor
Seal connections or install new fuel
hose
Saw chain rotates at idle speed
Engine idle speed too high
Reset low speed screw
L
correctly
Clutch does not release even
though idle speed is correct
Check the clutch
