Operation Manual

30
English / USA
HT 250
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
correct the setting of the high speed
screw within fine limits.
Standard Setting
: Shut off the engine.
: Check chain tension.
: Check the air filter and replace it if
necessary.
: Check adjustment of the throttle
cable and readjust if necessary –
see “Adjusting the Throttle Cable”.
: Check the spark arresting screen
and clean or replace if necessary.
H = Turn the high speed screw (H)
counterclockwise as far as stop –
no more than
3
/
4
turn
: Carefully screw the low speed
screw (L) down onto its seat
(clockwise) and then turn it 1 full
turn counterclockwise.
: Start and warm up the engine.
: Adjust idle speed with the idle speed
screw (LA) so that the chain does
not run.
Fine Tuning for Operation in
Mountains
A slight correction of the setting if the
high speed screw (H) may be necessary
if the engine does not run satisfactorily
when operating at high altitude.
Rule of thumb
Turn the high speed screw (H)
about one eighth of a turn for every
3300ft (1000 m) change in altitude.
: Check the standard setting.
: Warm up the engine.
: Turn the high speed screw (H)
slightly clockwise (leaner) – no
further than stop.
Adjusting the Carburetor
LA
H
L
1
250BA039 KN