Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1918-03-24
.s|MPL|F|ED LESSONS IN
CARE OF AUTOMOBILES
G1errlich Explains Zenith Carhurc.
tor in Language Layman Can
Comprehend.
ANSWERS MANY INQUIRIES
Explains to Car Owners How They
May Meet Problems Which Daily
Puzzle Thcm-Anothcr Chapter
on CarbIrctor Adjustment.
tCopyrirht. 1918. by Frederick G.
Guerrlich)
AUTO LESSON NO. So.

The zenith carburetor, an excellent
! carbure;or, which is coming into use
more and more, operates as REGARDS
having the mixture uniform for all
speeds on different principle from
practically all other carburetors.
We saw in studying the carburetor.
that as the engine speeded up. the
mixture gradually became richer, so
that Il was necessary TO furnish an
auxiliary mir valve which would auto
matically open AZ the higher speeds
and so permit the entrance OF extra air
into the mixing chamber o: the carbu-
rotor.
In the zenith no auxiliary air valve
is furnished. but instead 4 compound
nozzle is furnished, which will accom-
plish TIE same result the auxiliary
air valve.
In order TO understand the opera
ton OF this carburetor more thor
ouEhfy It is necessary that you be-
come acquainted with the principle OF
the compound nozzle around which the
zenith Is built To illustrate this prin-
ciple briefly let us consider the ele-
mentary type OF carburetor or mixing
valve, az shown in Figure /. 1t con-
sists of single Jet o. spraying noz-
zle placed in the path OF the incoming
air and fed from the usual float cham
Der. 1t In n natural inference to sup
pose that As the speed OF the motor
increases both this now OF air and Of
gasoline will increase in the same pro-
portion Unhappily, such Is not the
case There Is law OF liquid bodies
which states that the now OF gasoline
from the jet increases under suction
faster than the flow OF air, giving
mixture which grows richer and richer
"a mixture containing a much higher
percentage OF gasoline at high speed
than at low.
Now. IL we have a Jet which grows
richer as the suction increases, the
opposite type OF jet ia one which
would Grow leaner or weaker under
shown device in which the now OF
the gasoline is constant. A certain
fixed amount. determined by the open
ing l. is permitted to flow by gravity
into the we'll J. which we'll is open to
the air. Thus the amount OF gas
sprayed at the nozzle II will be con-
slant for all speeds and degrees OF
suction.
While the amount OF gas sprayed re-
mains tho same, as the engine Is speed
cd up and the suction increased more
air will he drawn up. and so the mix
turc Will become poorer and poorer
Ev combining these two types OF
nozzle. one of which gives i richer
mixture, Will" III" other gives a poor
for the other and so give q uniform
mixture.
In figure 8 Is shown the arrangement
OF the two no%2lcs or lets. The uoz-
zlcs giving the mixture which becomes
richer Is shown as G., the gasoline go
ing 10 il from the float chamber
through the pipe r. The other noz-
ale. which gives mixture which he
come; leaner. = shown as II. the outer
yyln No ir,a
the compensation ! and pipe r.
You will note that there Is no adj :
1usimrnt either on the nnazles or the
air The mixture can Only toe varied
by changing the nozzles. coirpensa-
tor or cir inlet pipes. When the car
Leaves the factory these will be right,
and should not be tanpercd with
For starting the engine a special
device Is used on this carburetor. the
regular nozzle being only partly used.
Figure shows this device. When
starting, the throttle valve r IS almost
entirely closed, and the gasoline is then
sucked through the passage j. enter
ing tho manifold above the valve. The
only adjustment on this carburetor IL
on this starting device. II is the screw
y.
Thus. II with t.hls carburetor the
starting 10 hard adjusting the screw
. may make the starting easier The
enlistment is very sensitive, and but
atight turn must be given at time.
As "a rule. one-quarter turn from the
closed position Will be the right Get
ting for this screw
Most carhuretors require that the
throttle lever be get open about one
third Us throw on the sector OF the
steering column when s,ar+inr hnt
with the Zenith the throttle mus. h.
almost closed. This is important
when the engine is quite warm. how
ever II may start better with the ,h-ot.
tie slightly open
Inc Zenith 70 always equipped with
choke valve, which must be ,,la
Closed when starting. II. however. the
engine does not start fairly promp,i,.
90 not crank for long time with
the choke valv" closed or tn. ca,hu.
rotor and eng in: will be flooded. shcuId
'his happen, ohm tho COMPRESSION
COCKS and blow the gasoline out nv
crankins the engine.