Opel Corsa B 1993–2000 Service and Repair Manual: 32 TL carburettor - adjustments

Note: Under normal operating conditions only the carburettor idle adjustments will need attention. Checking and adjustment of the following settings is not a routine operation and should only be necessary after carburettor overhaul or if the operation of the carburettor is suspect.

Fast idle

1. This operation may be carried out with the carburettor installed or removed. If the carburettor is removed, rotate the choke linkage on the side of the carburettor until the linkage arm is against its stop and the choke valve is fully closed.

2. With the linkage held in this position a small drill bit, of diameter equal to the fast idle valve gap given in the Specifications, should just slide between the throttle valve and the carburettor barrel (see illustration).

Using a drill bit to check the fast idle gap

3. If adjustment is necessary slacken the locknut on the fast idle adjusting screw (see illustration) and turn the screw as necessary to achieve the specified setting. Tighten the locknut after adjustment.

Fast idle adjusting screw (arrowed)

4. If the carburettor is in the car, first allow the engine to reach normal operating temperature and then if necessary adjust the idle speed. Also make sure that, when the choke knob is pulled fully out, the linkage rotates to the fully closed position with the linkage arm against its stop. If necessary adjust the choke cable .

5. Connect a tachometer to the engine in accordance with the manufacturer's instructions.

6. Start the engine and, with the choke knob pulled fully out, compare the engine speed with the fast idle speed setting given in the Specifications. If adjustment is necessary slacken the locknut and turn the fast idle adjusting screw to achieve the specified speed. Tighten the locknut after adjustment.

7. Switch off the engine and disconnect the tachometer.

Choke valve gap

8. Run the engine until normal operating temperature is reached and then switch off and remove the air cleaner.

9. Pull the choke knob fully out and check that the linkage rotates to the fully closed position with the linkage arm against its stop. If necessary adjust the choke cable.

10. With the choke knob still pulled out, start the engine and check that a drill of diameter equal to the choke valve gap dimension will just slide between the valve and choke barrel.

If necessary slacken the locknut and turn the adjusting screw above the vacuum unit until the correct gap is achieved (see illustrations).

Using a drill bit to check the choke valve gap

Choke valve gap adjusting screw (arrowed)

11. Switch off the engine, tighten the locknut and refit the air cleaner.

Accelerator pump delivery

12. With the carburettor installed, and the air cleaner removed, start the engine and allow it to idle for a few seconds, then switch it off.

13. Look down the carburettor barrel and open the throttle by hand. As the throttle is opened, a squirt of petrol should emerge from the accelerator pump jet. If no petrol is delivered, the pump is faulty or the jet is blocked.

14. The above check only serves to show whether or not the pump is working. For an accurate check, the carburettor must be removed.

15. With the carburettor assembled and the float chamber full of fuel, place the carburettor over a measuring cylinder. Take appropriate fire precautions.

16. Operate the throttle over its full stroke 10 times, taking about 3 seconds per stroke.

Catch the fuel delivered by the pump in the measuring cylinder. The desired delivery is given in the Specifications. No adjustment is possible: cleaning or renewal of the pump components will be necessary if the delivery is incorrect.