Engine Management; Adjusting The Carburetor - Stihl MS 880 Manual De Instrucciones

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Engine Management

Exhaust emissions are controlled by the
design of the engine and components
(e.g. carburation, ignition, timing and
valve or port timing).
44

Adjusting the Carburetor

General Information
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
correct the adjusting screws within fine
limits.
Standard Setting
Shut off the engine.
N
Check the air filter and clean or
N
replace if necessary.
Check the spark arresting screen
N
(not in all models, country-specific)
in the muffler and clean or replace if
necessary.
Turn high speed screw (H)
N
counterclockwise as far as stop (no
more than 1/2 turn).
Turn the low speed screw (L)
N
clockwise as far as stop, then turn it
back 1/4 turn.
Adjusting Idle Speed
Carry out the standard setting.
N
Start and warm up the engine.
N
Engine stops while idling
Set the low speed screw (L) to 1/4
N
turn open.
Turn the idle speed screw (LA)
N
clockwise until the chain begins to
run – then back it off 1/4 turn.
Saw chain runs while engine is idling
Set the low speed screw (L) to 1/4
N
turn open.
Turn the idle speed screw (LA)
N
counterclockwise until the chain
stops moving – then turn it another
1/4 turn in the same direction.
WARNING
If the chain continues moving when the
engine is idling, have your saw checked
and repaired by your servicing dealer.
Erratic idling behavior, poor acceleration
(even though low speed screw is open
1/4 turn)
Idle setting is too lean
MS 880