Fiat 903 CC Automobile User Manual


 
Float level - checking and adjustment
28 With the carburettor top cover held
vertically so that the float arm just touches the
fuel inlet needle valve ball, measure between
the float and the surface of the flange gasket
as shown in Fig. 13.36. If the dimension is not
within the specified tolerance, bend the float
tab which bears on the needle valve ball.
Fast idle - adjustment (requires
removal of the carburettor)
29 Close the choke valve plate by moving the
control lever fully. Retain the lever in this
position with a rubber band.
30 The throttle valve plate should now be
open to give a gap between its edge and the
progression holes as specified. Check the gap
using a twist drill of equivalent diameter.
31 If adjustment is required, release the
locknut and turn the adjustment screw.
Retighten the locknut.
Automatic anti-flooding device -
adjustment
32 Operate the choke valve plate lever fully.
33 Move the control lever on the automatic
anti-flooding device downwards to simulate
vacuum pull-down. The choke butterfly
should open, leaving a gap (B - Fig 13.38) as
specified. Measure the gap with a twist drill of
equivalent diameter and make sure that the
choke valve plate is in the position shown. If
adjustment is required, turn the screw on the
diaphragm unit.
Carburettor
(Weber 30/32 DMTE) - general
34 The carburettor is of twin barrel
downdraught type with a manually-operated
choke and an electronic fuel cut-off overrun
valve (photos).
35 Periodically, remove the large hexagonal
plug from its location at the fuel inlet pipe
stubs, and clean any dirt from the filter gauge.
13•64 Supplement: Revisions and information on later models
Fig. 13.37 Fast idle adjustment -
Weber 32 TLF carburettor (Sec 9B)
A = 0.65 to 0.75 mm (0.026 to 0.030 in)
Fig. 13.38 Automatic anti-flooding device
adjustment - Weber 32 TLF carburettor
(Sec 9B)
B = 4.5 mm (0.18 in)
Fig. 13.36 Float level measurement -
Weber 32 TLF carburettor (Sec 9B)
A = 26.75 to 27.25 mm (1.05 to 1.07 in)
9B.26F Main parts of the Weber 32 TLF
carburettor
9B.26E Throttle valve block gasket on the
Weber 32 TLF carburettor
9B.26D Extracting the throttle valve block
screws from the Weber 32 TLF carburettor
9B.26C Fuel inlet valve body and washer
removal from the Weber 32 TLF
carburettor
9B.34A Weber 30/32 DMTE carburettor
from anti-flood device link side