A person who specializes in carburetors or carburetion; a specialist in fuel-air mixing systems.
From 'carburetor' + '-est' (one who is or does), following English patterns of creating occupation nouns.
Mechanics who worked on carburetors were literally called 'carbureters' in the 1920s-1980s—now that skill is almost extinct, you'll never hear anyone ask for a 'carburetest' because the knowledge is historical.
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