D. CARBURETOR ADJUSTMENTS
●
●
●
Poor engine performance can be a result of
other causes such as dirty air filter, carbon
build-up on muffler outlets, etc. See the
“Trouble Shooting Chart” before proceed-
ing with carburetor a~ustments.
Forbest results, HUSQVARNA recommends
that you have a qualified service dealer
make all carburetor adjustments. Yourdeal-
erhasthe training,experience,andtoolsneces-
sarytoproperlyadjustyousawtomeetourfacto-
ryperformancespecifications.This service is not
covered by warranty. If it becomes necess
7
for
you to make carburetor adjustmentsyoursel ,fol-
low the described procedures very carefully.
The carburetor hasbeen a~usted at the fac-
tory for sea level conditions. Adjustments
ma~become necessaryifthe sawisused-atsignifi-
cantly higher altitudes or if you notice any of the
following conditions:
NQTIIGBesuretoproperlypreparethesawasde-
scribed in “l. Prepsration’ (below) before mak-
ing any adjustments.
– Chain moves when the engine runs at idle
speed. See “2. Idle SpeedAdjustment.”
– Saw will not idle, See “2. Idle SpeedAdjust-
ment” and “3. Low Speed Mixture Adjust-
merit.”
– Engine dies or hesitateswhen it should accel-
erate. See “4. Acceleration Adjustment.”
—
Lossof cutting powerwhich isnot correctedby
airfiltercleaning. See“5. HighSpeedMixture
Adjustment.”
ICAUTIO
N: I Permanent damage will occur to
any 2-cycle engine if incorrect carburetor
a~ustments are made.
“ :2L;::;2;&Y:t;:;i:;:&:”t\:r:zs:e:
qualified service dealer.
A WARNING
The chain will be moving during most of this
procedure. Wear your protective gear and ob-
serve all safety precautions.
o
N: I The air filter cover must be re-
1.
moved before making carburetor adjust-
ments. Before reinstallingthe air filter cov-
er, the air filter must be cleaned or engine
performance will be affected.
PREPARATION
a.
b.
c.
d.
e.
f.
Stop the engine.
Use a fresh fuel mixture with proper gasoline/
oil ratio.
Place the sawon a solid,flat surface and make
sure the chain will not contact any object.
Remove airfilter cover and clean the airfilter.
Locate the three (3) carburetor adjusting
screw openingsto the right of the airfiltercov-
er. Figure 42.
Startthe engine andallowengine to idlethree
(3) minutes to warmup. The engznemust beat
operating temperature for proper adjustments
to be made.
Choke
High Speed
Closed+
Mixture
b_/
,\
Screw
r
%
\\
K. ,
It
~ Low Speed
)
~ Mixture
Figure 42
2. IDLE SPEED ADJUSTMENT
a. Allow the engine to idle.
b. Adjust the idle speed screw until the engine
continues to run without stalling and without
the chain moving.
– Turn screw clockwise to increase engine
speed if engine stalls or dies.
– Turn screw counterclockwise toslowengine
downandlortokeepthechainfrom turning.
c. No further adjustments are necessary if
the chain doesnot move at idle speed and
if performance is satisfactory.
A WARNING
In “3. Low Speed Mixture Adjustment,” recheck
idle speed after each adjustment. The chain
must not move at idle speed and if performance
is satisfactory.
I
3. LOW SPEED MIXTURE ADJUSTMENT
4.
a. Allow engine to idle.
b. Turn the low speed mixture screw slowly
clockwise until the RPM starts to drop. Note
the position.
c. Turn the lowspeedmixture screwslowlycoun-
terclockwise until the RPM speeds up and
startsto drop again. Note the position.
d. Set the low speed mixture screw at the mid-
point between the two positions.
ACCELERATION ADJUSTMENT
Ifthe enginediesor hesitatesinsteadof accelerat-
ing, turn the low speed mixture screw 1/16 of a
turn at a time counterclockwise until you have
smooth acceleration.
HIGH SPEED MIXTURE ADJUSTMENT
5. ----
TIO
N: I Adjustments as small as 1/16 of a
turn can a-ff~ct-engine performance. It is
important to turn the screw only 1/16 of a
turn per adjustment and test the perform-
ance of the saw before making further ad-
justments.
a. Makea testcut.
b. Adjustthehighspeedmixturescrew1/16ofa
turnasfollows:
– Clockwiseif sawsmokesorlosespower.
– Counterclockwiseif thesawhasspeedout
ofthecutbutlackspowerinthecut.
c. Repeattestcut.
d. Continue1/16ofaturnadjustmentsuntilthe
sawrunssmoothlyincut.
A too lean high speed setting
(clockwise adjustment) will cause engine
– 19–
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