Chevrolet Light - Page 26

This carburetor has a vacuum controlled power jet and a
throttle operated accelerator pump to aid in pro viding the
desired economy and performance.
Description-Updraft Carburetor. The updraft carburetor
used on. the Cab-Over-Engine and Forward Control trucks is
mounted below the manifold. It is equipped with a vacuum
controlled power j et and a throttle operated accelerating pump
to aid in providin g the desired economy and performance.
Care. Tighten the carburetor to manifold and the manifold
to cylinder head stud nuts to prevent air leaks. Keep the car-
buretor clean externally and have it comple tely overhauled at
regular intervals so that foreign matter in the carburetor and
worn parts will not affect correct carburetion.
' Ig. 27_Downd, .. f, C .. ,b .... to,
Adj .. .,men'
Maintenance - Downdraft
Carburetor. There are but
two adj ustments on the car-
buretor, one for idling mix-
tur e and the other for idling
speed. These adjustments
sho uld be made together as
changing the adjustment on
one affects the other.
Run engine until it
reaches normal ope rating
temperature. Push cho ke
knob in all the way. Turn
idling mixture adjusting
screw "A" (fig. 27) in (clock-
wise) as far as it will go and
then back it off 1 0/4 turns.
Let engi ne idle at 450 to 500
revolutions pe r minute and turn idling mixture adjusting screw
"A" in or out as necessary to obtain a smoo th idle.
Before adjusting the idling speed make sure th e hand
throttle knob and choke knob are pushed in all the way and
that the accelerator and throttle linkage is free so that throttle
l ever stop screw "B" (fig. 27) is against the stop. Turn screw
" B" in or out to obtain an idling speed of 450 to 500 r evo lutions
.".