Mechanic was taking the overused desi path of "jaan chhurana".
Carburetors aren't supposed to be dumped when they become faulty; they can be rebuilt. Any competent mechanic can rebuild one (note the word competent).
Most mechanics don't want to mess with carb rebuilds; it takes a lot of time, expertise, and finesse. They just want an easy job for a quick buck. You'll need to find a competent mechanic that is well versed with carbys; in my experience they are a nearly extinct species in 2019.
Personally, I never let mechanics touch the carburetor; I've always worked on them myself.
