Suzuki Samurai 1986, Service Manual

Page: 124 / 482

[Primary main
system1
The fuel metered by the primary main jet is mix-
ed with the air from the primary main air bleeder
and then is discharged into the carburetor bore
through the main discharge nozzle. When the
plunger of the MCS is at the up position (i.e. the
ECM electrical signal is not received by the
MCS), the fuel orifice of the MCS is open. In
this state, the fuel is allowed to flow into the
fuel passage through this orifice in addition to
the main jet and the mixture becomes rich.
On the other hand, when the plunger is at the
down position (i.e. the ECM signal is received by
the MCS), the fuel orifice is closed. In this state,
the fuel flows into the fuel passage only through
the main jet and therefore the mixture becomes
lean. In this way, the mixture is maintained to
the optimum air/fuel ratio at all times by the
plunger which moves up and down at a frequen-
cy of 16 times per second according to the
from the ECM.
1. Primary main jet
2. Primary main air bleeder
3. Main discharge nozzle
4. Mixture control solenoid valve
5. Plunger
6. Fuel orifice
7. Fuel passage
Fig. 1-7 Primary main system
Secondary System
[Secondary slow system]
This system operates during the transition
period from the primary main system to the
secondary main system. When the primary
throttle valve is open nearly 54” and the vacuum
in “A” as shown in the below figure exceeds
specification, the diaphragm pulls up the rod.
In this state, the secondary throttle valve is
ready to open at any time when the primary
throttle valve opens further. When the secondary
throttle valve opens, the fuel discharged through
the secondary main jet is mixed with the air
from the economizer air bleeder at the secondary
slow jet. Then it is further blended with the air
from the secondary slow air bleeder and enters
into the carburetor bore through the idle down
channel.
1. Secondary main jet
2. Economizer air bleeder
3. Secondary slow jet
4. Secondary throttle valve
5. Secondary slow air bleeder
6. Idle down channel
Fig. 4-l-8 Secondary slow system
4-8