Fuel System; Air Filter - Stihl 4180 Series Manual

6.

Fuel System

6.1

Air Filter

Dirty air filters reduce engine power,
increase fuel consumption and
make starting more difficult.
The air filter must be cleaned when
there is a noticeable loss of engine
power.
– Close the choke shutter.
– Clean away any loose dirt from
around the filter and filter cover.
1
: Loosen the slotted screw (1) and
lift away the filter cover.
1
: Remove the filter (1).
The filter element is not washable. If
it is heavily loaded with dirt, fit a new
one.
Series 4180 Powerhead
1 2
: Take out the screws (1 and 2).
– Remove the air filter housing.
1
: Remove the paper gasket (1) and
fit a new one.
When reassembling, check that the
air filter housing is of the right type:
A B
: Air filter housing (A) without stub
for tank vent without return line,
b 6.5
: Air filter housing (B) with stub
(arrow) for tank vent with return
line to clean air side, b 6.5
Install air filter housing (B) with stub
only with the connecting hose to the
tank vent.
Unfiltered air would be sucked in if
the connecting hose is not fitted.
This would result in an increased
rate of wear and a risk of engine
damage.
Reassemble all other parts in the
reverse sequence.
– Tighten down screws on air filter
housing, b 3.4
– Tighten down screw air on filter
cover, b 3.4
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