CARBURETTOR
26 – English
Carburettor
!
Description
The diagrams with this description do not show the actual
carburettor on the chainsaw. They serve only to illustrate the
principles of arrangement and function.
Arrangement
The carburettor comprises three sub-systems:
• Metering unit, A in fig. 1.
• Mixing venturi, B in fig 2.
• Pump unit, C in fig. 3.
The metering unit (A) contains the jets and fuel control
function. It is here that the correct amount of fuel for the given
engine speed and power demand is metered.
In the mixing venturi (B), the choke, throttle butterfly valve
and diffuser jets are located. Air is mixed with the fuel to give
a fuel/air mixture that can be ignited by the ignition spark.
In the pump unit (C), fuel is pumped from the fuel tank to the
metering unit. One side of the pump diaphragm is connected
to the crankcase and pulses in time with the pressure
changes in the crankcase. The other side of the diaphragm
pumps the fuel.
Fig. 2 B
Fig. 3 C
Fig. 1 A
WARNING!
The fuel that is used in the chainsaw
poses the following hazards:
1. The fluid and its fumes are poisonous.
2. Can cause skin irritation.
3. Is highly inflammable.
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