Pablo
Looks like you are having a dilemma. I have your old carb here and I've found the problem took about 5 minutes to repair, do you want me to send it back? You and I did talk about low earth orbit for it.
I have your return address on the box and that is where I'll send it to unless you want it sent somewhere else. Let me know. As for the clip auto parts and cycle shops will have them they are called an e-clip I think. as for the size tell them its extra small.
Have a great day my friend.
Norman