Carburetor Adjustments - Shindaiwa 488 Owner's Manual

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CARBURETOR ADJUSTMENTS
Idle speed adjustment
Adjusting screw
Fuel mixture — AA
aimn
A
IMPORTANT!
Before attempting any carburetor
adjustments, inspect and clean the
engine air filter as described on page 23
of this manual.
Before starting the saw
1. Inspect saw chain tension, and
adjust if necessary. (see page 10)
2. Verify that the chain brake is
disengaged, and that the saw chain
is free to rotate.
Start the saw
Start the saw and warm the engine to
operating temperature. Place the saw
on the ground, and adjust the carbure-
tor as follows:
Idle speed adjustment
Use a screwdriver to slowly turn the
idle speed adjusting screw in or out
until the engine idles smoothly at
2600-8000 rpm.
WARNING!
The saw chain must.
never rotate at engine idle speed!
Low Speed (L) and High Speed (H)
Adjustment-Standard opening:
(1) EPA only
L...0~1/4 turns
(2) EMC only
L...1-1/4+1/4
H...1-1/4+1/4
EPA only
Low Speed Mixture (engine
idling; at operating temperature)
16
1. Using a small screwdriver, slowly
turn- the idle mixture screw
clockwise (lean mixture), and note
any changes in engine rpm.
2. Next,turn the idle mixture screw
counter-clockwise (rich mixture)
and note any changes in engine
rpm. f
3. Adjust the idle mixture screw to
provide the smoothest possible idle
with no sacrifice in acceleration,
4. If necessary, readjust the idle speed
screw for an engine idle speed of
2600-3000 rpm.
High Speed Mixture
High-speed mixture for the 488 saw is
factory-set, and cannot be adjusted in
the field.
EMC only
Adjustments for Low Speed (L)
Adjusting Screw-
After adjusting the low speed screw
according to the number shown above,
continue to turn gently either to right
or to left so that engine rotation may
be accelerated. Continuing to tun
will result in engine rpm decrease.
Return to the position just before this
slow-down and set at this point.
. If necessary readjust the idle speed
screw for an engine idle speed of 2600-
3000 rpm.
High Speed (H) Adjustment-
No adjustment is necessary when the
saw isnew. After approximately 10
hours use, rotare the H-needle
-clockwise to 1-1/4 turns (+1/4 turns).