7-2-9
Adjustment
Both
main adjusting screw and sl
ow
adjusting screw
can
be
adjusted in the
same
manner
as
in the
case
of
a single-
carburetor, and
both
right-hand and left-hand
ca
rburetors
are identical
in
construction. Ther
efo
r
e,
in this section, the
right
-hand carburetor
is
referred
to.
(1)
Ba
ck
out
the s
low
adjusting screw
from
a
lightly
seated
po
si
tion,
at the
same
time,
the setting
of
the main
adjusti
ng
screw should be adjusted
to
factory recom-
mended se
tting
.
/ _
-
--
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I
I
I
I
I
,
•
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I
1
1/
/'
~
,,....
. /
/
------
/ / -
----~
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r;;=;-
n,,- n-
,,-,
Fig. 7-29
(2) Start the engi ne and let it warm up.
(3) Inc
rease
the e
ng
i
ne
speed to
spe
cified r.p.m.
by
use
of
the
throt
t
le
stop screw.
•
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-
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r-
~
-
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•
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c
'
Fig. 7-30
(4)
Turn
the s
low
adjusting screw in
or
out
1 /8
turn
each
time
and when the idling
speed
reaches its
maximum
· and becomes stable, stop
turning
the
screw.
Adjust
the
throttle
stop screw once again, and set it
so
that
the
engine idle at specified r.p.m.
(5) Back
off
th
e slow adjusting screw 1
/8
turn.
Main Adjuster
Adjustment
The main adjusting-screw
is
used
to
adjust the air-fuel
mi
x
ture
when the snowmobile runs
at
high-speed.
Adjustment
should be made
so
that
the
mixture
becomes
as
rich
as
possible, provided
that
the engine
still runs
smoothly.
(This
is
necessary
to
prevent
engine overheating)
ENGINE
MAINTENANCE
-Carburetion and Fuel System
For adjustment,
follow
the
following
steps.
1.
First,
ba
ck
out
the main adjusting screw
as
specified.
2. To
ad
ju
st the main adjusting screws, run the snow-
mobile at high-speed and
find
the range
of
setting
positions (number
of
turns
out)
at
which
the engine
runs cle
an
ly
. Set the main adjusting screw
to
a
position where the richest practical
mixture
is
obtained.
For
this adjustment, the main adjusting
screw sh
ou
Id
be turned 1
/8
turn
or
less
each time.
/1
••
Fig.
7-31
3. To test the engin
e,
quickly
bring the
throttle
shutter
to
full-open
fr
om idling position and acceleration the
sn
owmo
bil
e.
Then, watch the performance
of
engine
operation.
4.
After
running
at
high speed, check the spark plug
for
col
orat
ion
for
an indi
ca
tion
of
carburetor
mixture
.
5. Run the snowmobile at high speed, and test
if
the
engine
will
pi
ck
up
speed
smoothly.
Repeat the
adjustments
as
specified
in
1-2
if
necessary .
•
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