まわす
to turn, to rotate
You take hold of it and turn it, which is the whole difference. A steering wheel does not go round on its own, and Ma まわ was す turning it all along: まわす.
回る まわる is a thing going round by itself. 回す is you turning it.
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Emaki is not affiliated with, or endorsed by, Kaishi 1.5k or its authors. The word, reading and meaning come from the Kaishi 1.5k deck, used with their permission. The mnemonic, the note and the kanji breakdown are original work, published under CC BY-SA 4.0.