Fuel
System
Carburetor
Sidedraft
LUA
Nikki
CARBURETOR ADJUSTMENTS
The carburetor mixture screws and the float level were
set for maximum efficiencyat thefactoryand willseldom
require readjustment.
If
adjustment seems necessary,
first be sure the ignition system is working properly and
is not the source of the problem.
~
Idle Mixture
Main
Mixture
1
to
1-112
1-318
to
1-518
1
to
1-1/2
1-1
/4
to
1-1
/2
1-1
/2
NA
If
adjustment
is
needed, refer to Figures
11
and
12
and
Table
1
and proceed as follows:
TABLE
1.
CARBURETOR ADJUSTMENTS
1.
Turn mixture screw(s) in until lightly seated, then
back them out the number of turns specified in
Table
1.
-1
f
oosen packing nut before turn-
ing main fuel adjustmenf and
tighfen
to
a snug
fit
after adjustment has been
made. Hold
the
adjustment while tighteningpacking
nut.
Failure
to
tigbfen
the
packing nut can
result
in
leaking fuel, creafing
a
serious fire hazard.
ACAUT~ON
Forcing the mixture adjusfment
I
screws
tight
wi//
damage the
needle and seat. Turn in only untillight tension can
be felt.
IDLE
ADJUSTMENT
SIDEDRAFT
CARBURETOR
2. Start the engine and allow it to warm up thoroughly
(at least
10
minutes).
3.
Move the engine speed control to the slow position.
4.
Determine if the engine has
a
governor low speed
adjustment screw (Figure 12).
5.
Pull the governor back (Figure 12)
so
the throttle
stop screw is against its stop. Continue to hold the
governor arm in this position while completing the
adjustments described in steps
6
through
8.
6.
If the governor does not have a low speed adjust-
ment screw, adjust the throttle stop screw to obtain
1200
rpm.
If
the governor does have a low speed
adjustment screw, adjust the throttle stop screw to
obtain 1100 rpm.
7A.
Sidedraft and
LUA
carburetors:
Turn the idle adjust-
ment screw in until engine speed drops and then out
until engine speed drops again. Over a narrow
range between these
two
settings, engine speed
will be at its maximum. Setthe idle adjustment screw
about
1/8
turn outward from the midpoint of this
range.
B.
Nikki
carburetor:
This carburetor has a limited
adjustment range between the stops of
k
1
/8
turn.
Adjust carburetor for highest rpm within this range.
8.
Re-adjust the throttle stop screw to obtain the rpm
specified in step
6
and release the governor arm.
LUA
CARBURETORS
LIMITER
CAP-
FS-1406-2
NlKKl
CARBURETORS
FIGURE
11.
MIXTURE
ADJUSTMENTS
15
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