Opel Corsa B 1993–2000 Service and Repair Manual: 1B1 carburettor - overhaul

Note: In the rare event of a complete carburettor overhaul being necessary, it may prove more economical to renew the carburettor as a complete unit. Check the price and availability of a replacement carburettor and of its component parts before starting work; note that most sealing washers, screws and gaskets are available in kits, as are some of the major sub-assemblies. In most cases it will be sufficient to dismantle the carburettor and to clean the jets and passages.

1. Remove the carburettor from the engine.

2. Detach the vacuum unit pull-down hose from the throttle body housing.

3. Remove the four retaining screws and separate the top cover from the carburettor body (see illustration).

Lifting off the carburettor top cover

4. Remove the idle speed and mixture adjustment screws, and the idle cut-off valve or plug (see illustration).

Adjustment screws and idle cut-off valve plug (arrowed)

5. If necessary the throttle valve lever, cam plate and return spring can be removed after removal of the shaft nut (see illustration). As they are removed, note their relative positions.

Throttle valve shaft lever and nut (arrowed)

6. Remove the two retaining screws and lift off the part-load enrichment device cover, spring and diaphragm (see illustration).

Removing the part-load enrichment device

7. Remove the accelerator pump collar, piston and spring (see illustrations).

Removing the accelerator pump collar . . .

. . . the piston . . .

. . . and the spring

8. Pull the accelerator pump delivery tube out of the carburettor body (see illustration).

Note the spring and ball.

Removing the accelerator pump delivery tube

9. Press out the float pin and remove the float and needle valve (see illustrations).

Removing the float . . .

. . . followed by the needle valve

10. Unscrew and remove the main jet (see illustration).

Removing the main jet

11. Remove the choke thermal and vacuum units by undoing the three retaining screws.

12. Unscrew and remove the idle fuel/air and auxiliary fuel/air jets from the carburettor body, taking note of the location of each (see illustration).

Idle (A) and auxiliary (B) fuel/air jets

13. Further dismantling is not recommended. Clean and inspect the various components.

14. Reassembly is a reversal of the dismantling procedure. Note that float level is not adjustable on this carburettor.

15. After refitting, adjust the idle speed and mixture setting then carry out the other adjustments.