Toyota 3R-B 1969, Repair Manual

Page: 73 / 193

5-4 F U E L S Y S T E M - Tr o ub le Shooting, Ca rburet or
4. N oisy fuel pump
a. L o o s e fuel pump mounting
b . Worn o r defective r o c k e r arm
c . Broken o r w eak ro c k e r arm
spring
5. E x c e s s iv e fuel delivery
Improper fuel pump spring
C A R B U R E T O R - On R S , R T 4 3 L
& R T 5 2 L S e r i e s
Tighten mounting bolts
Replace r o c k e r arm
Replace spring
Replace with a p r o p e r spring
Description
T h e ca rb u re to r installed on the R S 5 0 , R S 5 6 , R T 4 3 L and R T 5 2 L s e r ie s is a
t w o - b a r r e l type to insure efficient p erform an ces of the carb uretor under various
operations. It is similar to two single b a rr e l carb u retors built into one single
unit with special featu res. T h e prim ary system incorporates a double type ven­
turi while the secon dary system is provided with a triple type venturi. Each
system consists of the air horn, main n ozzle and the throttle va lv e . One set
fo rm s the prim ary while the other set form s the secondary side. T h e primary
system com poses of the low speed, high speed, p o w e r va lv e, accelerating,
choke system and the thermostatic valve systems which enable to supply the
air-fuel mixture f o r normal operation. When the throttle valve is opened w ide fo r
full load o r fo r acceleration, the secondary system also operates to supply the
air-fuel mixture together with the prim ary system. T h e throttle valves of both
the prim ary and the secondary systems a r e operated with linkage, and a re inter­
locked enabling the throttle v a lve s to w ide-open positions at the same tim e. T h e
high speed valve installed in the secondary system together with the p o w e r valve
enables the p erfo rm a n ces extrem ely smooth.
Specification:
T y p e
Float level:
at raised position
at lo w e re d position
A i r horn outer diameter
P r i m a r y venturi inner diameter:
main
small
S e c o n d a r y venturi inner diameter:
main
la rg e
small
Th rottle b o re diameter: prim ary
secondary
Main jet diameter: prim ary
secondary
S lo w jet diameter: p rim ary
S lo w a ir b le e d e r diameter: N o . l
N o . 2
D o w n -d raft, tw o -b a rre l
9 . 3 mm (0 . 366'
(0.867
(2.758
2 2 . 0 mm
70 mm
23 mm (0.906
9 mm (0.355
29
15.5
7
35
35
1.06
1.45
1.50
0.47
0 .7
1.3
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
(1.143
(0.611
(0.276
(1.379
(1.379
(0.042
(0.057
(0 .0 5 9
(0.019
(0.028
(0.051
on 5R
on 3 R - B , 3 R - C