89
MS 271 C, MS 291 C
12.6.5 Adjusting Screws
Grommet has been removed for the
sake of clarity.
There are three adjusting screws on
the carburetor:
H
= high speed screw (1)
L
= low speed screw (2)
LA
= idle speed screw (3)
If the carburetor cannot be adjusted
properly, the problem may be the
adjusting screws.
The high speed screw
H
has a
limiter cap, which has to be
removed before the screw is
removed.
Always install a new limiter cap.
– Remove the carburetor,
b
12.5
– See also carburetor
troubleshooting,
Low speed screw
:
Take out the low speed screw
L
(1).
5902RA404 TG
3
1
2
5902RA405 TG
1
:
Inspect the tip (arrow) for
damage or wear and replace the
low speed screw (
L
) if necessary.
– Screw down the low speed screw
(
L
) as far as stop.
– Continue with the high speed
screw
H
.
High speed screw
The high speed screw
H
has a
limiter cap, which has to be
removed before the screw is
removed.
:
Screw the puller (1)
5910 890 4502 about 5 turns
counterclockwise into the limiter
cap
– left-hand thread.
Do not turn the puller any further
– the high speed screw (
H
) may
otherwise be damaged.
5902RA406 TG
1
5902RA407 TG
:
Pull out the limiter cap (1).
The polymer segment is left on the
high speed screw (
H
) after the
limiter cap has been pulled off. It is
necessary to unscrew the high
speed screw (
H
) to remove the old
polymer segment.
– Take out the high speed screw
(
H
).
Always install a new limiter cap.
:
Inspect the tip (arrow) for
damage or wear and replace the
screw (
H
) if necessary.
:
If the high speed screw (
H
) is in
order, remove the old polymer
segment (1)
– take care not to damage the
high speed screw (
H
).
1
5902RA408 TG
1
5902RA409 TG
