Zenoah GZ4350, Workshop Manual

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33
- English
Repair Instructions
WARNING!
The fuel used in the chain saw has
the following hazardous properties:
1. The fluid and its vapour are
poisonous.
2. Can cause skin irritation.
3. Is highly inflammable.
7.16 Carburettor
Description
The images for this description do not correspond
to the carburettor on the chain saw. They purely
show the principle for the design and function. The
carburettor is based on three sub-systems:
Metering unit
The needles and the fuel’s control functions are
located in the metering unit A. Here the correct
fuel amount is adjusted for the current speed and
power output. See figure 26.
Pump unit
In the pump unit C fuel is pumped from the fuel
tank to the carburettor’s 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. See figure 28.
Mixing venturi
The mixing venturi B houses the choke, throttle
valve and diffuser jets. Here, air and fuel are mixed
to create a fuel-air mix that can be ignited by the
ignition spark. See figure 27.
Fig 26
Fig 27
Fig 28