Service Manual
7. The pilot jet may be removed next. The pilot
jet is a
#40
and can be cleaned or replaced.
Fuel flows through the small opening in the
end of the jet and air enters through the
holes in the side. The opening on the top
has no function as it is plugged.
The pilot screw controls air in the pilot
circuit. It should be open one full turn. See
Fig. 3-6.
Figure 3-6
8.
Carburetor disassembly is completed by
removing the choke and throttle shafts and
the main nozzle. The bowl gasket
is
also
replaceable and should be removed prior to
service or cleaning of the carburetor. See
Fig. 3-7. To withdraw the choke and throttle
shaft, the choke and throttle plates must be
removed. Each plate is retained with two
screws.
Throttle Shaft
Gasket
Nozzle
Figure 3-7
Service Carburetor
The metallic body of the carburetor may be
cleaned in carburetor cleaner. Plastic parts may
be damaged by some carburetor cleaners.
Carburetor passages may be cleaned out with
compressed air.
CAUTION!
Be sure
to
wear
safety glasses when
using
compressed air.
Replace any components that show wear or
damage. The inlet needle is replaceable but the
seat is not.
If
it is suspected that the seat is leaking, the
carburetor can be pressure tested after it has
been cleaned. Use Toro pressure tester, num-
ber 41-7910. If the seat is good, it will hold
.5
kg/cm2 (7 psi) for at least
10
seconds. This
procedure should be completed with the car-
buretor turned upside down
so
the float holds
the needle closed. See Fig. 3-8.
If
the pressure
leaks down, replace the needle and try the test
again.
If
the carburetor fails again, the seat is
bad and the carburetor must be replaced.
Figure 3-8
Reassembly Carburetor
1. Install the choke and throttle shafts. Check
Fig. 3-3 and 3-7 for proper orientation of the
shafts.
2. Install the choke and throttle plates. Use a
thread locking compound such as Loctite
271 on the screws.
3. Replace the main nozzle and bowl gasket.
4. Install the pilot jet and pilot screw. See Fig.
3-6. The pilot screw should be one turn open.
5.
Hook
the inlet needle into the float and
secure the float and needle in place with the
hinge pin. See Fig. 3-9.
13