self-starter vs starting motor

self-starter and starting motor both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-starter	Yes	No	No	No
starting motor	Yes	No	No	No

As nouns, starting motor is a hypernym of self-starter; that is, starting motor is a word with a broader meaning than self-starter:

self-starter: an electric starting motor that automatically starts an internal-combustion engine
starting motor: an electric motor for starting an engine

Other hypernyms of self-starter include starter, starter motor.

self-starter (noun)	starting motor (noun)
an electric starting motor that automatically starts an internal-combustion engine	an electric motor for starting an engine
an energetic person with unusual initiative