That is a picture of a throttle body.
 

Ig,

Recently scrapped an old chevy that i had revived.

It had sat for 2-3 years as well and would not start unless gas was
poured to it.

I disconnected the return line from the throttle body and a bunch of
yellow crap came out while cranking over.

While this was happening truck started.

So i shut it off and hooked return line back up.

Ran fine from then on.

Hood blew up in my face on highway so i scrapped it....

Good luck.