TOHATSU MX 50D2 Service Manual page 162

Fuel System
4) Choking Passage (#2 and #3 carburetor)
a
å
k
a - Air intake
b - Air-bleed inlet
c - Slow air jet
d - Bypass port
e - Pilot screw
f - Idle Port
g - Throttle valve
Choke system consists of choke valve, detent and push-pull. When starting cold engine, the operator should judge whether
it is necessary to operate the choke to make engine starting easier, and if necessary, to operate the handle of choke cable
manually to set it to a proper position.
When attempting to start cold engine, pull choke lever to close choke valve. When engine starts, low pressure (vacuous)
area is formed in the venturi on the back of choke valve. Then, the fuel goes through main nozzle, bypass port and idle port,
and sucked into carburetor bore, where it is mixed with air that runs in from opening of the choke valve to form thick air-fuel
mixture.
As engine warms up, operate choke cable manually to open choke valve. When engine has warmed up to a temperature
suitable to the operation. Set choke lever to its original position.
4-16
b
c
j
d
i
h - Fuel inlet
i - Main jet
j - Slow jet
k - Choke valve
å Air
∫ Air-fuel mixture
e
f
g
∫
h
2st 50D2 2011
GB