Husqvarna 225 HBV - Manual (Page 20)

18
– English
MAINTENANCE
The fuel quantity required in relation to the air flow,
provided by the opening in the throttle, is adjusted
by the L and H jets. If they are screwed clockwise,
the air/fuel mixture becomes leaner (less fuel) and if
they are screwed counterclockwise, the mixture
becomes richer (more fuel). A leaner mixture gives
rise to a higher engine speed and a richer mixture
gives rise to a lower engine speed.
The T screw regulates the idling speed. Turning the
T screw clockwise will increase the idling speed;
turning it counterclockwise will lower the idling
speed.
The carburetor has been carefully preset at the fac-
tory. However, additional adjustment may be required
due to climate, altitude, gasoline and type of two-
stroke engine oil used. The instructions below
describe how carburetor adjustment should be
carried out.
Function
Carburetor
The carburetor governs the engine speed via the
throttle. Air and fuel are mixed in the carburetor. The
air/fuel mixture is adjustable. To utilize the blower’s
maximum output, the settings must be correct.
The carburetor has three means of adjustment:
H = High speed jet
L = Low speed jet
T = Adjustment screw for idling
The carburetor is preset to the basic settings when
the blower is tested at the factory. These basic
settings are the following:
The H screw has been turned counterclockwise
to its end position against the stop.
The L screw has been turned counterclockwise
to its end position against the stop.
The recommended idling speed is 3000 rpm.
Basic (factory) settings
H L T
Adjustment
NOTE!
Do not remove the stops in the H and L
jets. If these stops are removed, the
blower will no longer satisfy the
environmental requirements established
by the California Air Resources Board.
Low speed jet, L
1. Check that the blower tube (15) and the nozzle
(14) are mounted on the blower.
2. Turn the H and L adjustment screws fully counter-
clockwise so that they rest against the stop.
3. Start the blower engine, see page 13, and
alternate letting it run at idling speed and at half
throttle for 1-2 minutes to warm up. If the engine
will not run at idling speed, turn the T screw
clockwise until it does.
4. Set the T screw to the setting, at which the engine
runs precisely at idling speed, but not faster.
5. Make a fine adjustment, turning the L screw so
that the engine will run at max. idling speed. Then
turn the L screw max 1/4 of a turn
counterclockwise.
6. Then turn the T screw to increase the engine
speed, if necessary.
NOTE!
When setting the H jet, the max.
permissible full-throttle interval is 10
seconds, after which the engine must run
at idling speed for at least 10 seconds.
High speed jet, H
1. Start the blower as described on page 13 and
alternate letting it run at idling speed and at half
throttle for 1-2 minutes to warm up.
2. Give the engine full throttle and adjust the H
screw until the engine runs at maximum speed.
3. Turn the H screw 1/8 of a turn counterclockwise
(less than 1/8 of a turn if the stop restricts this
adjustment).