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covered
by these
instructions are
supplied with Zenith marine
type
safety non-drip
carburetors,
ex-
cept the V-8
models
(See
special
V-8
instruction books.)
With
the
exception
of
the
following
ad-
justments,
maintenance of the car-
buretor
by
the
operator
is
not
recommended.
If difficulties arise
which
are not
correctable
by the
following adjustments, it is recom-
mended
that
the
carburetor
be
sent to
the UNIVERSAL
factory for
repair or replacement.
a. Adjustment of
Throttle Stop
Screw, Idle Needle Valve and
:Main Jet
(1)
Before
any
of the
above
ad-
justments
to
the
carburetor
are
made,
the engine should
be opera-
ted
for
a
sufficient
length
of
time to
reach
operating
tempera-
ture.
(2) With
throttle in
idling posi-
tion,
adjust
the
throttle
stop
screw
for
desired
idling speed.
See Fig. 65 and 66.
(3)
Turn
the
idle
needle
valve
in
and
out
until
the
speed
of
the engine
is steady
and as
fast
as
this
throttle
position will
permit.
(4)
Readjust
the
screw
for
desired
speed.
throttle
stop
engine
idling
(5) Open the throttle approximately
one-third.
(6) Loosen the
packing nut
on the
main jet adjustment.
(7)
Turn
the main
jet
adjustment
screw in until
the engine speed is
noticeably reduced.
(8) Turn
the main
jet
adjustment
screw
out
until
the engine
runs
smoothly and as fast as this throt-
tle position will permit.
-51-
(9) Hold
the
adjusting
screw
in
place and tighten
the packing nut.
(10)
Return
the
throttle to
idle
position
and readjust
idle needle
valve
slightly
for
best
idling
performance.
b. Carburetor
The carburetors
used on
six
cyl-
inder gasoline
marine
engines are
the Zenith updraft type
with both
idling and high-speed
adjustments.
Each has a large air entrance whose
bowl shaped
bottom acts
as a drip
collector with automatic drain.
A properly
adjusted
should be left alone.
carburetor
If the
fuel is
free from
dirt or
other
impurities,
the
carburetor
should not clog up or give trouble.
We
recommend
that a
large
size
fuel
strainer be
inserted
in the
gasoline
line
between
the
fuel
pump
and
carburetor to trap
dirt
and condensation.
Since
a
marine
engine
operates
under
more
or
less
steady
load
conditions,
it
is
comparatively
easy to- adjust the carburetor.
To
facilitate
adjustment of
the car-
buretor
it is fitted
with an
id-
ling jet "A",
high speed jet
"Btl,
choke
"C"
and
idling
adjustment
screw "D" as shown in Fig. 68.
When adjusting your carburetor,
be
sure
that
the
flame
arrestor is
clean
and
free
of
obstructions,
and that the choke "C" is wide open.
1;'arm the engine
up thoroughly be-
fore attempting the adjustment.
With the engine idling turn the id-
ling jet
"A"
slowly to the
right
and left until the setting is found
that
will
let
the
engine
idle
smoothly and as fast as that throt-
tle setting will permit. Adjust the
idling adjustment screw "D"
to the
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