The daily star-mirror. (Moscow, Idaho) 1911-1939, 1923-09-28
j. s. EXPERIMENTS
CUT COST OF Gas
Adjustment of CarburetorS on
Government Trucks Reduces
Consumption of Fuel.

WashingtOn.-Subs savings of
gasoline by the periodical adjustment
of carburetors based on the results of
analysis of exhaust gases from auto
mobile engines are said to be feasible
by the Department of the Interior
following experiments made by the
bureau of mines on the fleet of motor
trucks used by the government fuel
yard in Washington. AS the result of
carburetor adjustments made by gas
analysis in the bureaus experiments,
an actual increased efficiency in mile
age and saving of gasoline amounting
to % per cent was attained. The tests
demonstrate that a portable carbon
dioxide Indicator for testing the ex-
haust gases of motor vehicle gives a
positive indication of the carburetor
adjustment, removes all guesswork OF
such adjustment and is perfectly feas-
ible practically.
Samples of Gas Tested.
The government fuel yard trucks
tested by the bureau of mines ranged
in capacity from two and a half to
seven and a half tons. During the
winter months, when the demand for
coal is heavy, from 80 to 80 trucks
are used. Samples of the exhaust gas
were taken on the trucks kept in
service for summer hauling in order
to determine the carburetor adjust
ment as used. Changes then were
ment whenever possible, without sac
riflcing fexibuity of operation and
power. In all but one case the car
buretors were found to be adjusted top
rich for maximum power and economy.
Increase in Mileage Noted.
The actual Increase in mileage and
saving of gasoline due to the carbure-
tor adjustm ents made by gas analysis
when the month previous and the
month following the adjustments are
compared, showed an increase in mhe-
age of % per cent; for the second
month after adjustment, 16 per cent,
and for the third month, 8 per cent.
When the mileage is compared truck
for truck, and not taking into consid-
GRAFTON the distance each Travelled dur
ing the month, the increased mileage
equaled PAT, PIP and 1862 per cent,
The adjustment of carburetorS by
of exhaust gas is based upon
the fact that the carbon dioxode in
The exhaust is a direct Indication of
he air-fuel ratio and completeness of
combustion. In turn, the air-fuel
alto and completeness of cOmbuS-
ion tell whether the carburetor is
properly adjusted for maximum power
md gasoline economy.
Adjustment Usually Rich.
Other conditions being constant, the
Mileage obtainable varies as the per-
entage of carbon dioxide in the ex-
aust gas and airfuel ratio. This has
cen little realized by most garage |
len in the past. Usually the adjust |
lent is far too rich for maximum
economy. There are, however, excep-
ions to this rule determination of
he carbon dioxide content of the ex-
aust gas while the vehicle is being !
perated on the road gives a positive
ldication of the carburetor adjust
tent.
The results Of the bureau Of mines
Iperiments show that adjustable car
1retors tend to become more richly
ijusted with lapse Of time, and that
lie adjustments should be checked at
asst every two months to maintain the
ost economical adjustments.
Driving is a Big Factor.
The bureau suggests that one driver
ay be able to get considerable more
lleage than another, due to the
ethod of driving. The mileage is
eatly increased by disengaging the :
itch whenever possible and coast :
g. In approaching a heavy grade
ff1cient momentum should be OBJ
ined to carry the vehicle consider !
lie distance up the grade before max J
G it necessary to change the gears.
Weather has q marked effect on the =
lleage obtainable. In general, mo-
r runs better at higher humidity and