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- - - - - - - - - - - - E N G I N E SERVICE MANUAL
D. After disassembly of carburetor, clean all
parts in a grease solvent.
Air dry all
parts instead of using cloth to avoid ac-
cumulation of lint. To remove gummy de-
posits in parts
,
float bowl, needle valve,
idle tube, adjustment screw, etc. use al-
cohol. Remove gasket material and clean
all gasket surfaces thoroughly.
NOTE: Clean out high speed needle valve
opening with
1/
16" drill to make sure it
is clean.
E. Inspect needle ends of idle adjustment and
main adjusting screws and inlet needle for
bent or scored tapered ends.
Replace
damaged needles; do not attempt to repair
them. Make sure needle valve seats are
not damaged.
F. Inspect reed valve surface of adapter be-
fore installing. Surface must be absolute-
ly clean and reed must be installed to
completely cover intake hole and lay per-
fectly flat against the adapter. Reed is
made with a slight bend in
it
to apply
tension against adapter and act as an in-
let valve. Dirt or grit on surface or an
incorrectly positioned reed can cause blow
back through carburetor.
G. Reassemble carburetor in reverse order
of number sequence on exploded view.
Parts are numbered in order of disas-
sembly.
Use all new gaskets and use new packing
for main adjustment screw. Thread new
packing on main adjustment
screw,
with
the black face away from needle. Thread
packing far enough on screw to expose
three or four threads. Install screw into
carburetor body far enough to gently seat
needle point. Install packing nut so that
it is tight against the packing. Back main
adjustment screw away from seat 1-1
/
4
to
1-1/
2 turns.
NOTE: Before assembling main adjust-
ment screw, the packing nut and packing
must be removed and reassembled as di-
rected above.
If
nut and packing are not
removed
.
and installed correctly,
small
pieces of packing will be pushed into fuel
channels causing restrictions to fuel flow.
H. Check carburetor float setting.
Use idle
tube as gage for
1/
16 -
3/
32
"
distance
between bowl cover flange and nearest edge
of float when bowl cover assembly is in
inverted position. Bend tab on float for
correct setting.
See figure 16.
If
car-
buretor has a plastic float measure
in
same manner
,
setting distance at
5/
16",
IDLE
TUBE
Figure 16. Adjustment of Float
I. Install carburetor and adapter assembly
on engine. Install
ai
r cleaner assembly,
making sure it has been thoroughlyclean-
ed.
Adjust carburetor using the following screws:
MAIN ADJUSTMENT SCREW - Controls power
range mixture
IDLE MIXTURE SCREW - Governs idle mix-
ture at closed throttle
IDLE SPEED REGULA TING SCREW - Con-
trols required idling speed
A. INITIAL ADJUSTMENT: Completelr close
the IDLE MIXTURE SCREW by turning in
without forcing until seated.
Then turn
screw in opposite direction one turn. Pro-
ceed in like manner with MAIN ADJUST-
MENT SCREW except open one and one-
half full turn after first being closed. Now
choke and start engine in usual manner
and run until thoroughly warm.
B. MAIN ADJUSTMENT SCREW ADJUST-
MENT: With speed control lever set at
fast position, slowly turn MAIN ADJUST-
MENT SCREW inward until motor begins
to lose speed. Then slowly turn
screw·
in
opposite direction (usually
1/
Bth to
1/
4th
of a turn) until maximum speed and power
is obtained which is then final adjustment
setting.
C. IDLE MIXTURE SCREW: This adjustment
should only be made AFTER the above
mentioned MAIN ADJUSTMENT SCREW
has been completed. Close throttle and
allow engine to idle at slightly faster than
17
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