Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1921-05-01
|bUERRL|CH AGAIN talks
bARBURETOR ADJUSTMENT
fsDiscusscs the Zenith and Tells of
Advantages in Its Opcr-
alton.
%HAS OMPOUN NOZZLE
Especial Device Is Used for Starting
9 tho Enginc-Uniform Mixture Is
Assured by Combining Two Types
of Nozzle.
las COMPOUNp NoZZLE
AUTO LESSON .i3.
Carhuretor Adjustment.

E,i The Zenith carburetor, an excellent
SScarouretor. which is coming into use
more and more. operates. as regards
s having the mixture uniform for all
Gspecds. on a different principle from
I. practically all other carburc;ors
We saw, in studying the carnureior.
StSthat as the engine specdcd up the
s3mixture gradually became richer, SO
THAT II WAS necessary to furnish
ssSan auxiliary air valve which would
open at the higher
Espeeds, and so permit the entrance
sSof extra air into the mixing chamber
y Of the carburetor.
ss In the Zenith no auxiliary air
sANalHc is furnished. but. instead. a
sscompound nozzle is furnished. which
Evil accomplish the same result as
4 the auxiliary air valve.
sge In order to understand the opera
gEtion OF this carburctor more thor
ssoughly IL is necessary that YOU he
sEcome acquainted with the princip!"
of the compound nozzle around which
the Zenith is built. To illustrate this
s principle briefly Let US consider the
elementary type OF carhurrior OF
\ mixing valve, IS shown in Hi-ure
1t consists OF a single jet OF spray
ling nozzle placed in the path 81 the
! Incoming air and fed from tn. usual
E float chamber. 1t is a natural INFER
once to suppose that as the speed OF
the motor increases both the How
of air and OF gasoline Viii inCrcas"
In thc same proportion. tnhappi!N
law. OF liquid bodies which states
that the flow OF gasoline from the
jet increases under suction faster
than the flow o! air. giv!n: a mixture
which grows richer and riCher---a
mixture containing much higher
percentage of gasoline a; high speed
than at low.
Now. IL We have a Jet which grows
richer as the suction increases, tho
opposite type OF jet is ono which
would grow lcancr or weaker under
similar conditions. In Figure is
shown n dcvIc" in which tho t'ow OF
the gasoline is constant. y certain
fixed amount determined 10y the
opening !, is permitted 10 flow ~
is open to The air. Thus tho amount
of gas sprayed at the nozzle II viii
be constant for all speeds and de-
GrecS of suction.
remains the same. rs the engine is
specded up and the suction Increased.
more air will be drawn up. ANA 50
the mixture Will become poorer and
poorer.
by combining these two types of
nozzle. one OF which gives richer
mixture. whhe the other gives "a
poorer mixture. the one will. com
pensatc for the other and 50 give
a uniform mixture
In Figure IS shown tho arrange
ment OF the TWO noZzlcS or jets Tn"
nozzlcs giving the mixture which he
comes richer is shown as .. the gas
olinc going TO il from tn" float cham
Der through tho pipe T.. Tho other
becomes lcaner, is shown as II the
outer nozzle. the rasolin" gong to
IT through the compensation ], and
You Will note tina, there is no adj
tnstment either on the MOBILES or
Slhe air. The mixture can only be
varied by chaneins The nozzles COM
pefirator or air inlet pipes. When
the car leaves the factory these win
be right, and should not be tam
For starting the engine "a special
device is used on this carburctor. the
regular MOBILES being only partly
used. Figure shows this device.
is almos, entirely closed. and the
gasoline is then sucked through tho
passage j. entering the manifold
above the valve. The only adjust
Nment. on this carburetor is on this
starting device. II is the screw -
Thus. ii with this carburetor mo
starting is hard. adjusting the screw
% may make the starting easier. The
adjustment is Very sensitive. and hut
slight turn must he given at Il
TIME. AS a rule ono quarter turn
from the closed position viii bc IN.
right setting for this screw
Most carburctors require ina, tho
throttle lever he set open about one
third its throw on the sector 81 the
steering column when siny,inc.. lint
almost closed This As -.nfuSrt.,ui
hen he cnGir" IL quite w:tri, how
eyer, II may start better with Tho
throttle slightly open
The Zenith is always equipped with
CHOKE valve, which must hc hold
closed when starting. II, how, ~
the engine does not start sairIy
time with the choke valve closed or
the carhurctor and cnsiu. viii be
hooded should this happen. op.n
the compression cocks and blow tho
gasoline our by "rankinf the engine