Arctic Cat ZR 900 Series 2006 Operator's Manual page 50

Fine-Tuning Fuel Mixture
Screws, Air Screws, and Idle
Speed Screw
1. While counting the rotations,
carefully rotate the fuel mixture
screws clockwise until lightly
seated.
! CAUTION
D o n o t forc e a f u e l m i xt u r e
screw when rotating it clock-
wise; damage to the fuel mix-
ture screw taper will result.
2. Rotate the fuel mixture screws
counterclockwise the exact
number of rotations ± 1/4 turn
from the seated position as an
initial setting.
! CAUTION
The fuel mixture screw setting is
very critical to engine perfor-
mance; therefore, do not rotate
the fuel mixture screws less
than the recommended number
of turns counterclockwise or
engine damage will occur.
3. While counting the rotations,
carefully rotate the air screws
clockwise until lightly seated.
! CAUTION
Do not force an air screw when
rotating it clockwise; damage to
the air screw will result.
MAINTENANCE
4. Rotate the air screws counter-
clockwise the exact number of
rotations ± 1/4 turn from the
seated position as an initial set-
ting.
5. With the snowmobile on a
shielded safety stand, start the
engine, release the brake lever
lock, and thoroughly warm up.
! WARNING
It is important that the rear of
the snowmobile is on a shielded
safety stand. If not, personal
injury could result.
! WARNING
DO NOT stand behind the snow-
m o b il e o r n e a r t h e ro t a t i n g
track. NEVER run the track at
high speed when the track is
suspended.
0735-774

NOTE: Make engine idle adjust-
ment only after the engine has
reached running temperature.
Allow engine to warm up for 2-3
minutes.
6. After the engine has been thor-
oughly warmed up, fine-tune
the idle speed screw until the
engine idles smoothly.

NOTE: If a tachometer is being
used, engine idle speed should
be approximately 1500 RPM.
! WARNING
If a tachometer is not available,
care must be taken not to adjust
engine idle speed too high.
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