O.S. Engines 21VZ-R - Manual (Page 15)

Mixture Control Valve
Carburetor Body
First rotate the Mixture Control
Valve until its slotted head is
flush with the carburetor body.
This is the standard position.
CARBURETOR CLEANLINESS
The correct functioning of the carburetor depends on
its small fuel orifices remaining clear.
(See Care and Maintenance section on Page17.)
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Slide Valve
Carburetor Body
Metering Needle
REALIGNMENT OF METERING NEEDLE AND
MIXTURE CONTROL VALVE
First rotate the Metering
Needle until its slotted head is
flush with the carburetor body.
This is the standard position.
In the course of making carburetor adjustments, it is
just possible that the Metering Needle and the Mixture
Control Valve may be inadvertently screwed in or out
too far and thereby moved beyond its effective
adjustment range.
Its basic position can be found by rotating the
Metering Needle and Mixture Control Valve until its
slotted head is flush with ball link the carburetor body.
Ball Link
15