Husqvarna 525P4S Workshop Manual page 38

Repair instructions
The carburetor's design
A
The carburetor can be divided into three different A
functional units: the metering unit, the blending
unit, and the pump unit
The metering unit
The needles (A) and the fuel control functions are
located here.
The needle valve (B) and control diaphragm (C)
are vital to the carburetor's function.
C
B
The blending unit
In this section of the carburetor fuel and air are
mixed in the proper proportions.
D
The choke valve (D) and throttle valve (E) are
E
placed here.
In the middle of the venturi (narrowest part of the
throughput) the main jet (F) is found.
F
The pump unit
This is where the pump diaphragm (G) that pumps
fuel from the tank to the carburetor's measuring
unit is found.
The diaphragm is affected by pressure variations in
the engine's crankcase via an impulse channel (H.
If the channel is blocked, by grease or a wrongly
facing gasket, for example, the pump unit does not
function and the engine cannot be started.
H G
38
- English