carburetor vs mechanical device

carburetor and mechanical device both are nouns.

Word	Noun	Adjective	Verb	Adverb
carburetor	Yes	No	No	No
mechanical device	Yes	No	No	No

As nouns, mechanical device is a hypernym of carburetor; that is, mechanical device is a word with a broader meaning than carburetor:

carburetor: mixes air with gasoline vapor prior to explosion
mechanical device: mechanism consisting of a device that works on mechanical principles

carburetor (noun)	mechanical device (noun)
mixes air with gasoline vapor prior to explosion	mechanism consisting of a device that works on mechanical principles