Choking Passage - TOHATSU MFS 9.9 Owner's Manual

Fuel System

5) Choking Passage

a - Air intake
b - Choke valve
c - Bypass port
Choke system consists of choke valve, detent and push-pull cable or electric solenoid. 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 or to activate the solenoid for electric starting model.
When attempting to start cold engine, pull choke lever or activate the solenoid 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 or turn off the solenoid to open choke valve. When engine has warmed up to
a temperature suitable to the operation. For manual choke system, set choke lever to its original position.
4-10
b
a
c
e
d - Idle Port
e - Main nozzle
d
4st 9.9/15/20 2008