Carburetor - Toro 71202 Operator's Manual

Carburetor

To adjust the carburetor, you will need a tachometer
to set the idle speed. If you do not have a tachometer
or the special knowledge required to adjust the
carburetor, contact an authorized service dealer.
IMPORTANT: Before you adjust the
carburetor: (1) check the throttle control and
adjust it if required; refer to Throttle and
Choke Control, page 26, and (2) check the air
cleaner and clean it if required; refer to Air
Cleaner, page 28.
POTENTIAL HAZARD
The engine must be running for you to
adjust the carburetor. This potentially
could be unsafe.
WHAT CAN HAPPEN
If you contact a rotating blade or engine
blower screen, touch a hot muffler, or the
tractor accidentally moves, you or
bystanders could be seriously injured or
killed.
HOW TO AVOID THE HAZARD
Although the engine must be running, set
the parking brake, shift into neutral, and
disengage the blade control (PTO). Do not
touch rotating engine blower screen or the
hot muffler.
1. Initial Adjustment
A. Gently turn the idle mixture screw (Fig. 27)
clockwise until it just closes. Do not force
(tighten) the idle mixture screw because the
carburetor could be damaged.
B. Open the idle mixture screw (Fig. 27) one
turn counterclockwise. This setting allows
you to start the engine.
C. Start the engine, move the throttle to
"SLOW" and let the engine idle for
five minutes.
3
2
Figure 27
1. Idle mixture screw
2. Idle speed screw
2. Final Adjustment
A. Hold the carburetor throttle arm against the
idle speed screw (Fig. 27). Adjust the idle
speed screw so the engine idles at 1750
rpm. Check the rpm with a tachometer.
B. While you continue holding the throttle arm
against the idle speed screw, slowly turn the
idle mixture screw (Fig. 27) in (clockwise)
until the engine begins to slow (lean
mixture). Next, turn the idle mixture screw
out (counterclockwise) until the engine
begins to run roughly (rich mixture).
C. Now rotate the idle mixture screw (Fig. 27)
midway between the lean and rich mixture
until the engine runs smoothly.
D. Make sure the idle speed is still 1750 rpm.
Adjust the idle speed screw if required;
step 2A.
E. Move the dash-mounted throttle lever from
"SLOW" to "FAST." If the engine does not
accelerate smoothly, turn the idle mixture
screw counterclockwise to a slightly richer
mixture.
Maintenance
1
477
3. Throttle arm
27