Carburettor (Weber 32 ICEV 50/250/1) - servicing and adjustment

Fuel system / Carburettor (Weber 32 ICEV 50/250/1) - servicing and adjustment

1 The carburettor top cover with float may be removed without the need to withdraw the carburettor from the manifold. The other adjustments described will require removal of the carburettor.

2 Unscrew the filter plug from the top cover, clean the filter screen and refit it.

3 Extract the top cover fixing screws, lift the cover and tilt it to unhook it from the diaphragm capsule link rod.

4 Access to the fuel inlet needle valve is obtained by carefully tapping out the float arm pivot pin. Take care, the pivot pin pillars are very brittle.

5 Check that the needle valve body is tight otherwise fuel can bypass the needle valve and cause flooding.

Float adjustment
6 Reassemble and check the float setting. Do this by holding the top cover vertically so that the float hangs down under its own weight.

Measure dimension (A) (Fig. 3.10) which should be between 1 0.50 and 11.10 mm (0.41 to 0.44 in) with the gasket in position. If necessary, bend the float arm tab to adjust.

7 Now check the float travel which should be 45.0 mm (1.77 in). If adjustment is required, bend the end of the float arm.

Accelerator pump stroke
8 Using a twist drill as a gauge, open the throttle valve plate through 3.5 mm (0.138 in).

9 Turn the nut on the accelerator pump rod until it just makes contact with the pump control lever.

Fast idle adjustment
10 With the choke valve plate fully closed by means of the control lever, the throttle valve plate should be open (dimension A) (Fig. 3.1 2) between 0.75 and 0.80 mm (0.030 and 0.032 in). Adjust if necessary by means of the screw and locknut.

Anti-flooding device
11 This consists of a diaphragm capsule and link rod.

12 The condition of the diaphragm can be checked by applying a vacuum source to the hole in the throttle valve plate block. The vacuum pressure will drop if there is a leak.

13 Actuate the choke valve plate lever fully and depress the control lever of the anti-flooding device to simulate operating vacuum.

14 There should be a gap (Y) (Fig. 3.15) between the edge of the choke valve plate and the wall of the carburettor throat of between 3.75 and 4.25 mm (0.148 and 0.167 in). Any adjustment that may be needed should be carried out by bending the link rod.

Fig. 3.10 Float setting diagram (Weber 32 ICEV 50/250) (Sec 9)

A = 10.5 to 11.0 mm (0.41 to 0.44 in) B = 45.0 mm (1.77 in)

Fig. 3.11 Accelerator pump setting diagram (Weber 32 ICEV 50/250) (Sec 9)

X = 3.5 mm (0.138 in)

Fig. 3.12 Fast idle adjustment diagram (Weber 32 ICEV 50/250) (Sec 9)

A = 0.75 to 0.80 mm (0.030 to 0.032 in)

Fig. 3.13 Anti-flooding device (Weber 32 ICEV 50/250) (Sec 9)

Y = 3.75 to 4.25 mm (0.148 to 0.167 in)

Fig. 3.14 Anti-flooding device vacuum intake (Weber 342 ICEV 50/250) (Sec 9)

1 Vacuum intake hole

Fig. 3.15 Choke valve gap opening (Weber 32 ICEV 50/250) (Sec 9)

Y = 3.75 to 4.25 mm (0.148 to 0.167 in)