what is this on the engine that the breather goes to

[hward1]

this isnt my engine just a pic off of mud - but mine is missing this metal thing that the breather goes into -- what does it do and do i need to get one - thanks

 

[GeologistFelix]

Sucks hot air off of the exhaust manifold to get it running faster in cold weather. Unless you spend a lot of time in places that get into the negative digits in the winter, it's not really an important part.

 

[2mbb]

there is supposed to be a corrugated tube that fits around the "breather" and connects to the port on the bottom-side of the air cleaner inlet. There is a vacuum operated diverter plate in the air cleaner inlet that pulls hot air off the exhaust manifold when the engine is cold.