Toyota 3R-B 1969, Руководство по ремонту

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F U E L S Y S T E M - Ca r b u r e t o r 5-7
air -fu<
T h e fuel from the float chamber flows through the main jet, then to the slow
jet ( 1 ) , and mixes with the air from the prim ary air b leeder N o . l . A fte r
passing through the econom izer (2 ) , mixes with the air from the prim ary
air bleeder N o . 2 ( 3 ) , and flows down into the slow port ( 5 ) , and the idle
port (6 ) to be discharged in spray form into the intake manifold.
When the throttle valve (4) starts to open slightly, and as the edge of the
throttle valve moves past the slow port ( 5 ) , the intake manifold vacuum is
applied onto the slow port ( 5 ) , and this port starts discharging the
mixture same as the fdle port (6) .
3. P r im a ry high speed system
This system is provided to supply
the air-fuel mixture fo r interme­
diate throttle opening o r part-load
operating requirements.
Th e main nozzle (3 ) located in
the small venturi (4 ) supplies the
fuel mixture during the operation
with the valve partially to fully
opened position.
Pa ssin g through the primary main
jet ( 1 ) , the fuel mixes with the
air from the main air b leeder ( 2 ) ,
and flows up the main n ozzle.
H e r e , the mixture is atomized,
through the air horn.
F i g . 5-5 P r im a r y High
S p eed System
G1736
and is mixed with the air stream flowing
4. S econd ary high speed system
T h e more the engine p o w e r is de­
sired , the m ore of air-fuel mix­
ture is requ ired. T h e secondary
high speed system is so deviced
to meet this requirement, and con­
sists of the secondary main jet (1) ,
main air b leeder (2 ) , main nozzle
( 3 ) , small venturi ( 4 ) , secondary
throttle valve (5) , high speed valve
( 6 ) , secondary b o r e ’ (7) and the
high speed weight le v e r ( 8 ) .
F ig . 5-6 S e co n d a ry High Y6714
T h e high speed valve is installed S p eed System
with a balancing weight ( 9 ) , and
is retained with a nut at the end of the shaft. A s the a c c e le ra to r pedal is
dep ress ed , and the prim ary throttle valve opens approximately 6 0 ° , the
linkage opens the secondary throttle va lv e , and also both va lves a r e fully
opened at the same time.
H o w e v e r , while the engine revolution is not high enough, the high speed valve
remains closed even though both v a lves a re fully o p en ed , and the secondary
high speed system remains inactive. T h is causes the air flow through the
primary venturi to quicken accomplishing a complete atomization of the fuel