Decompression Valve - Husqvarna K970 III Workshop Manual

6.6.11 High and low speed jets
The low and high speed nozzles on the carburetor are
set in the factory. They must not be adjusted.
6.6.12 To adjust the idle speed
Use a special screwdriver, refer to
overview on page 10 and a tachometer, refer to
Servicing tools overview on page 12 . Make sure that the
cutting blade is installed.
Note: Do not connect the tachometer directly to the
ignition system. The tachometer senses the magnetic
field from the ignition system.
Note: Do not remove the air filter cover.
WARNING: Adjust the idle speed outdoors. The
exhaust fumes are poisonous.
1. Operate the product for approximately 5 minutes
until it is warm.
2. Keep the instrument with the arrow down to the
position of the spark plug.
42 - Repair and servicing
Servicing tools
3. Adjust the idle screw to an idle speed of
approximately 2700 rpm.
If the cutting blade rotates at this speed, do a check of
the clutch.

6.7 Decompression valve

6.7.1 Decompression valve function
The decompression valve decreases the compression in
the cylinder when the engine starts. A small quantity of a
mixture of fuel and air goes through the decompression
valve (A). The valve closes because of the combustion
pressure when the engine fires (B).
A B
1444 - 001 - 02.04.2020