Husqvarna 445 - Chain Catcher, Hand Guard, and Vibration Damping Checks; Muffler Maintenance and Spark Arrestor

English – 33
Repair instructions
WARNING!
he fuel ue in the chaina ha
the flling haaru prpertie
 he ui an it fue are
poisonous.
2. Can cause skin irritation.
  highl inaale
7.15 Carburettor
Description
The drawings accompanying this description do not
correspond with the carburettor on the chainsaw.
They only show the principle for the design and
function.
Design
The carburettor is based on three sub-systems:
• The metering unit, A.
• The mixing venturi, B.
• The pump unit, C.
In the pump unit (C), fuel is pumped from the fuel
tank to the metering unit. One side of the pump di-
aphragm 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 gure 24)
The jets and the fuel’s control functions are located
in the metering unit (A). Here the correct quantity
of fuel is adjusted for the actual speed and power
output. (see gure 22)
The mixing venturi (B) houses the choke, throttle
valve and diffuser jets. Here air is mixed with the
fuel to give a fuelair miture that can be ignited by
the ignition spark. (see gure 23)
A
C
B
Fig 24
Fig 23
Fig 22