Ok, to start off I have a 76 F250 Custom with a 360 engine and from what I can identify with the carburetor tag is a Motorcraft 2100. I tried to tweak the idle a bit so it would run smother and lean it out so it could pass smog. Doing this caused the engine to flood to the point that gas comes out of the carb on the top and spills over until the engine shuts off. I tried turning the screws back to there original position but that didnt stop it from doing this every time it idles for a few seconds. What would cause this? I figured it was time for a carb rebuild. So I did some research and my carb does not look like the motorcraft 2100 I found on the internet. Does that matter? And lastly what or where should I buy the rebuild kit from. Sorry so many questions just wanna get it right.

Ford Motorcraft 2100 2150 2 barrel carburetor Parts Page (website I found that doesnt look like mine)

 

You either have a piece of debris in the needle and seat or the float has stuck. Either way you will need to pull the top to investigate. The mixture screws have no connection to that issue. Just a coincidence.

 

Agreed, your needle is stuck open. As said above, it's just a coincidence. Time for a rebuild.

That carburetor is definitely a Motorcraft 2100. However, that doesn't matter when you buy the rebuild kit. You must use the tag (first picture). Write that number down and give it to the parts guy to look up in the book. Don't buy a "one size fits all" kit from AutoZone etc. I stick with Napa for that stuff because the guys here look it up in their book and cross reference it to the exact kit.