Air Filter Maintenance; Carburetor Adjustment; Adjusting The Carburetor - Toro 51903 Manuel De L'utilisateur

Air Filter Maintenance

Note: CLEAN AND RE-OIL THE AIR
FILTER EVERY 10 HOURS OF
OPERATION. Your unit's air filter is
one of the most important areas to
maintain. If it is not maintained, you
will void the warranty. Before
cleaning, make sure the unit is turned
off.
1. Remove the screws on each side of the
carburetor/air filter cover assembly. Remove the
air filter cover (Fig. 11).
Note: The choke lever must be in the
"CHOKE" position to remove and
install the air filter cover.
2. Remove the air filter (Fig. 26).
3. Wash the filter in detergent and water (Fig. 27).
Rinse the filter thoroughly and allow it to dry.
4. Apply enough clean SAE 30 oil to saturate the
filter (Fig. 28).
5. Squeeze the filter to spread the oil (Fig. 29).
6. Reinstall the filter (see Fig. 26), air filter cover
and screws (see Fig. 11).
Note: If the unit is operated without the
carburetor/air filter cover assembled,
you will void the warranty.

Carburetor Adjustment

This unit is equipped with a diaphragm-type
carburetor that has been carefully calibrated at the
factory. In most cases, no further adjustment is
required.
Note: To meet the 1995 California emission
regulations, the carburetor has
adjustment needle limiter caps to
restrict the amount of adjustment.
The condition of the air filter is important to the
operation of the trimmer. A dirty air filter will restrict
the air flow, which upsets the fuel-air mixture in the
carburetor. The resulting symptoms are often
mistaken for an out-of-adjustment carburetor.
Therefore, check the condition of the air filter
before adjusting the carburetor. Refer to Air Filter
Maintenance.
If the following conditions are experienced, it may be
necessary to adjust the carburetor:
The engine will not idle
The engine hesitates or stalls on acceleration
The loss of engine power that is not corrected by
cleaning the air filter and muffler
Note: Careless adjustments can seriously
damage your unit.

Adjusting the Carburetor

1. Clean the air filter if it is dirty. Refer to Air
Filter Maintenance.
2. Make the initial settings with the engine stopped.
These initial settings should allow you to start
and warm up the unit before making the final
adjustments.
Initial Idle Speed Setting
A. For Walbro carburetors: Back the idle
speed screw (Fig. 30) out
(counterclockwise) until it does not contact
the carburetor throttle lever. Then turn the
screw in (clockwise) until it just begins to
move the throttle lever; then continue
turning 2 full turns.
B. For Zama carburetors: Back the idle speed
screw (Fig. 31) out (counterclockwise)
until it does not contact the throttle valve
located inside of the carburetor. This is
accomplished by carefully watching for the
movement of the throttle lever to stop. Then
turn the screw in (clockwise) until it just
begins to move the throttle lever, then
continue turning 1 1/2 turns.
EN–10