Tube from exhaust to intake

[weezzell_5400]

I am in the middle of a rebuild 1999 5.7 mercruiser 2 Barrel.......there is a tube that goes from the exhaust manifold to the intake manifold ....I figure that its some sort of emissions ...but can't figure out how it works exactly ....I took the intake manifold off to put on new block and was blowing all ports out with compressed air ...and parts cleaner ...but the hole for the tube seems clogged or something.....is it supposed to be blocked off for a heat exchange or what .....thanks in advance

 

[Bt Doctur]

the tube supplies the hot air from the exaust port to warm the carb ,

 

[weezzell_5400]

Thanks for the quick answer.....I was hoping it was something along thise lines and not something clogged that I couldn't see or get to ...