Note: Before you begin, see. Chapter 2. A tachometer and exhaust gas analyzer will be required to check idle speed and mixture. If the cooling jacket was removed, new O-rings will be required for installation.
Removal
1. Proceed as described in Chapter 17, points 1 and 2.
2. Note the position of the bimetallic casing alignment marks to facilitate installation, if necessary, make marks yourself, then unscrew the three fastening screws and remove the bimetallic casing. Move the casing to the side, be careful not to deform the coolant hoses or the electrical wiring of the throttle valve heater.
3. Unscrew the three screws securing the throttle housing to the carburetor body, remove the throttle assembly, making sure that the throttle drive rod does not bend.
4. If it is necessary to remove the bimetallic casing for replacement, proceed as follows:; otherwise go to point 8.
5. Mark the position of the automatic choke coolant hose to facilitate installation, then disconnect the hoses. Plug the hoses or secure them with the ends facing up to prevent coolant loss.
6. Disconnect the electrical wiring from the electric damper heater, remove the bimetallic casing.
7. The cooling jacket can be separated from the bimetal jacket by unscrewing the central fastening bolt. Remove the O-rings from under the bolt head and from the cooling jacket frame.
Installation
8. Position the throttle assembly on the carburetor body; make sure that the lever on the damper assembly engages with the drive rod. Tighten the three mounting screws.
9. Check and, if necessary, adjust the choke clearance and fast idle cam position as described in steps 15-19 of this Chapter.
10. Connect the bimetallic spring to the throttle lever, place the bimetallic casing on the throttle casing, install the fastening screws. Align the marks on the bimetallic casing and the throttle casing as noted before removal, then tighten the fastening screws.
11. Where applicable, install the cooling jacket to the bimetal jacket using a new O-ring, connect the coolant hoses and the throttle body heater wiring.
12. Then carry out the installation in the reverse order, paying attention to the following.
13. If the coolant hoses have been disconnected, check the coolant level as described in Section 3.
14. Check and, if necessary, adjust the high idle speed as described in points 25-34 of this Chapter.
Adjustment
Air damper clearance
15. After removing the bimetallic casing as described in points 2-4, proceed as follows.
16. Press the damper lever all the way clockwise and secure it in this position with a rubber band.
17. Move the throttle lever to the fully open position, and measure the air gap between the bottom of the throttle and the wall of the primary chamber. Check that the gap matches the data in Specifications.
18. If necessary, adjust the air damper clearance by bending the "adjustable part (2)". If the clearance is too small, increase the clearance "B" with a screwdriver. If the clearance is too large, decrease the clearance "B" with pliers (see illustration).
19. After adjustment, install the bimetallic casing as described in points 10-14.
Fast Idle Cam Position
20. After removing the bimetallic casing and correctly adjusting the air damper clearance "B", proceed as follows.
21. Open the throttle valve, then close the air valve by lightly pressing the valve drive lever with your finger (see illustration). Close the throttle valve.
22. Check that the high idle speed adjusting screw touches the stop on the second stage of the fast idle cam.
Fuel and exhaust systems - carburetor models
23. If adjustment is required, first check that the throttle return spring is correctly positioned, then make the adjustment by bending the lever.
24. Install the bimetallic casing as described in points 10-14. Increased idle speed.
Note: An accurate tachometer and exhaust gas analyzer are required to perform the adjustment (cO meter).
25. Check the idle speed and mixture as described in Chapter 14. Before attempting to check or adjust high idle speed, set the idle speed correctly.
26. Warm up the engine to normal operating temperature, connect the tachometer according to the manufacturer's instructions, and then proceed as follows.
27. Place the high idle speed adjusting screw on the second step of the fast idle cam (see illustration).
28. Start the engine without touching the gas pedal and check that the increased idle speed is within the specified limits. If adjustment is required, turn off the engine and proceed as follows.
29. Remove the plug from the high idle speed adjusting screw(see illustration).
30. Check that the adjusting screw rests on the second from the top step of the fast idle cam, then start the engine without touching the gas pedal.
31. Turn the adjusting screw with a screwdriver until the high idle speed value specified in the Specifications is obtained.
32. If the cooling fan turns on while making adjustments, stop making adjustments and continue only after the fan turns off.
33. After completing the adjustment, turn off the engine and disconnect the tachometer.
34. Install a new plug on the high idle speed adjustment screw.
Material copied from this resource: OPELBOOK
Visitor comments