Carburetor Adjustments - Craftsman WEEDWACKER 358.798490 Operator's Manual

SERVICE AND ADJUSTMENTS
Carburetor adjustment is critical and tf done improp-
erly can permanently damage the engine as well as
the carburetor, Please read all instructions and con.
suit the Troubleshooting section of this manual
before beginning this process. If the engine does not
operate according to these instructions after repeat-
Ing the adjusting steps, do not use the unit. For fur-
ther assistance, please call our customer assistance
hotline at 1-800-235-5878,
WARNING:
MAKE CARBURETOR ADJUSTMENTS
WITH THE LOWER END SUPPORTED TO
PREVENT SEMI-AUTOMATIC HEAD FROM
CONTACTING ANY OBJECT. HOLD UNIT
WITH YOUR HAND.
THE SEMI-AUTOMATIC HEAD WILL BE
SPINNING DURING MOST OF THIS PRO-
CEDURE, WEAR YOUR PROTECTIVE
EQUIPMENT AND OBSERVE ALL SAFETY
PRECAUTIONS.
IN MIXTURE ADJUSTMENT, RECHECK
IDLE SPEED AFTER EACH ADJUSTMENT.
If engine does not start, it may be flooded If in doubt read
the section on flooded engine in the starting section of
this manual prior to beginning any adjustments.
The carburetor has been adjusted at the factory for sea
level conditions. Adjustments may become necessary if
the unit is used at significantly higher altitudes or if you
notice any of the following conditions:
. Engine will not idle. See "idle Speed Adjustment" and
'Mixture Speed Adjustment".
. Engine dies or hesitates when it should accelerate See
"Acceleration Check"
° Loss of cutting power which is not corrected by air fil-
ter cleaning. See "Mixture Speed Adjustment"
NOTE: There are two adjustments on the carburetor.
• The Idle Speed Adjustment.
, The Mixture AdjustmenL
CARBURETOR PRESETS (Fig. 31)
If your engine will not start due to suspected improper
carburetor adjustment, the following presets may be
required, If used, it is recommended that all steps within
the adjustment procedure be completed in order to
assure a properly set carburetor. If presets are not need-
ed, proceed to section "Idle Speed Adjustment",
Very _mall adjustments can affect engine performance. It
is important to make slight adjustments and test pedor-
mance before proceeding. Each adjustment should be no
more than 1/t6th of a turn
• Turn the mixture adjustment fully counterclockwise to
the limiter cap stops.,
; Turn idle speed adjustment clockwise one full turn,
If engine fails to start after pedorming carburetor pre-
sets, the unit may be flooded. Review the "Difficult
Starting" section of the manual If problems continue,
call the 1-800 number listed on the front cover of this
manual for further assistance°
° Starl the engine and operate for three (3) minutes to
warm up Go to "Adjusting Procedure".
AIR FILTER
IDLE SPEED SCREW COVER
Figure 31
ADJUSTING PROCEDURE
IDLE SPEED ADJUSTMENT
. Allow the warm engine to idle
= Adjust the Idle Speed until the engine continues to run
without stalling,
- Turn screw clockwise to increase engine speed if
engine stalls or dies,
- Turn screw counterclockwise to slow engine down
- Follow instructionsin "Acceleration Check".
• No further adjustments are necessary if performance
is satisfactory
MIXTURE ADJUSTMENT
, Support the lower end so the semi=automatic head is
off the ground and will not make contact with any
object, Be sure the trimmer line is extended to the max-
imum length allowed by the line limiter.
° Start the engine. Allow engine to idle, then squeeze
throttle trigger fully
NOTE: Perform steps below at full throttle
• Turn mixture screw counterclockwise to the limiter cap
stop.
= Run engine at full throttle for 30 seconds.
° I! engine is running rough, turn mixture screw clockwise
in 1/16th turn increments until engine just starts to run
smoothly.
• Do not attempt to adjust screw beyond stops as dam-
age will occur,
. After completing adjustments, check for acceleration.
° tf the unit accelerates and runs smoothly, no further
adjustments are necessary. 1! not, proceed to
"Acceleration Check"
ACCELERATION CHECK
° Allow engine to idle
• Squeeze trigger fully
- if performance is satisfactory (engine accelerates
smoothlY)r no further adjustments are necessary.
- If the engme does not accelerate smoothly, turn
the mixture screw counterclockwise a small amount
(no mote than the width of the slot in the adjusting
screw).
• Repeat step above until smooth acceleration is
obtained. Do not attempt to adjust the screw beyond the
stop as damage will occur.
NOTE: It may be necessary to repeat "Idle speed
Adjustment"through "Acceleration Check,"_o obtain coro
rect adjustments
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