English - 39
WARNING!
The fuel used in the chain saw has
the following hazardous properties:
1. The uid and its vapour are
poisonous.
2. Can cause skin irritation.
3. Is highly inammable.
7.14 Carburettor
Description
The gures accompanying this description do not
correspond with the carburettor on the chain saw.
They show only the principle of design and func-
tion.
Design
The carburettor is based on three sub-systems:
• Pump unit, A.
• Metering unit, B.
• Mixing unit, C.
In the pump unit A, fuel is pumped from the fuel
tank to the carburettor’s metering unit. One side
of the pump diaphragm is connected to the crank-
case and pulses in time with the pressure changes
in the crankcase.With the help of inlet and outlet
valve in diaphragm, the fuel is transfered through a
lter screen to the inlet needle. See gure 27.
A
The fuel control unit is attached to the metering
unit, B. Here the correct quantity of fuel is adjusted
for the actual speed and power output. See gure
28.
The mixing unit C houses the choke, the throttle
valve and the diuser jets. Here air is mixed with
the fuel to give a fuel/air mixture that can be ignited
by the ignition spark. See gure 29.
B
C
Fig 28
Fig 29
Fig 27
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