He's a 'mechanical' genius. [=he is a person who is very smart about machines]
He's not 'mechanically' inclined. [=he is not knowledgeable about machinery]
The flight was delayed because of 'mechanical' problems/difficulties.
(..) But this is always like this, always hanging out. And they keep doing like this and the thing falls down. Then they wanna go ride this mechanical animal and fall and bust their face, you know... ''l rode the bull at Gilley's and busted my face,'' you know. A picture of an idiot in action. (..)1983 Bill Cosby: Himself