Questions and maybe problems...

Hey guys still a little new to this...

I have a couple of questions.

1. What does that part in the picture do?
2. I went to change the spark plugs and one of them had a fitting on the outside of it (makes the thread of the spark plug fatter) what is that called?

its the electric choke,and 2nd question is that would be the helicoil come out

would messing around with it stop the car from starting or idling properly??

i meant in regards to the electric choke

yep