Adjusting The Carburetor - Dolmar PS-460 Manuel D'emploi Et De Sécurité

Adjusting the carburetor

CAUTION:
Do not adjust the carburetor until the machine has been
completely assembled and checked! Do not adjust the
carburetor without a tachometer!
Carburetor adjustment is necessary for optimum engine
performance, for safer and more economical operation.
Adjust the carburetor only with the engine warm, a clean
air filter, and properly installed cutting tool.
Carburetor adjustment may be done only by a DOLMAR
service center. Improper adjustment can cause damage
to the engine.
In order to comply with new emissions legislation, limits have
been placed on the carburetor adjusting screws (H) and (L).
This limitation (to about 180 degrees) prevents an exces-
sively rich mixture. This in turn ensures compliance with
emissions rules as well as optimum engine performance and
economical fuel consumption.
You will need a tachometer (part No. 950 233 20) for op-
timum adjustment. Exceeding the maximum permissible
speed can lead to overheating and under-lubricating, and
damage to the engine!
Factory setting of adjusting screws (H) and (L): Turned out
almost all the way (counterclockwise).
Use a screwdriver (blade width 4 mm, part No. 944 340 00)
to adjust the screws.
For proper adjustment, proceed as follows:
Checking adjusting screw (H)
Before starting the engine make sure that adjusting screw (H) is
turned out counterclockwise until it reaches a noticeable stop.
The limitations do not prevent excessively lean running!
1. Start engine and let it warm up (3-5 minutes)
2. Set idle
3. Check acceleration
4. Set maximum permissible speed
5. Check idle speed
2. Set idle
Set the idle speed per the technical specifications.
Turning the adjusting screw (S) in (clockwise) increases the
idle speed. Turning it out (counter-clockwise) lowers the idle
speed. The cutting tool must not rotate!
3. Check acceleration
When the throttle is pressed, the engine should go smoothly
from idle to high speed.
Turn adjusting screw (L) out (counterclockwise) in small
increments until acceleration is good.
A
4. Set maximum permissible speed
Set the maximum speed by minimal adjustments of
the adjusting screw (H) in accordance with the tech-
nical specifications. Turning the adjusting screw (H)
clockwise increases the speed. Never exceed the
maximum permissible speed!
For units with electronic engine speed limitation:
No tachometer is necessary to determine the
maximum permissible speed, since exceeding
this speed will result in clearly audible ignition
misses!
5. Check idle speed
Check the idle speed after setting the top speed (the
cutting tool must not rotate!).
Repeat the adjustment procedure starting at Step 2,
until the engine runs with the correct idle speed, good
acceleration, and maximum permissible speed.
S H L
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