Idle Adjustment Screw
 

Does anyone know where I can find one for a 1972 Mercedes 250??? Mine fell out and now my car is idling at like 90,000 RPMS! Help

Spring too
 

I also lost the spring!

I am not sure what screw you are talking about. If it was the little brass screw in the base plate of the carburator that is the idle mixture screw. Please refer to this diagram. http://i151.photobucket.com/albums/s131/Blue72W114/CarbINAT32.jpg

If you are talking about # 13 and 14 then you are talking about the mixture screw. That would explain your problem. However, if you are talking about # 34 which is the cold idle speed screw, then when you removed it the idle would be low when cold.

I have a couple of them that I would be willing to mail to you. Send me a PM with the parts that you need and your email and I will get back to you.

When you get the part you will need to tune the carbs back into spec. Read and understand this manual before doing anymore tinkering.
http://jaimekop.com/CarbManual/index.html

You will note that the proper way to adjust for idle speed is # 67 in the diagram, not any screws.

Hope that helps