Cut down on tips for how engine works (3)
I believe the answer is:
hew
'cut down' is the definition.
(thesaurus)
'on tips for how engine works' is the wordplay.
'on' is a charade indicator (letters next to each other).
'tips for' says to take the final letters (I've seen 'tip for' mean this).
'engine works' becomes 'he' (I can't justify this - if you can you should give a lot more credence to this answer).
The last letter of 'how' is 'w'.
'w' put after 'he' is 'HEW'.
Can you help me to learn more?
(Other definitions for hew that I've seen before include "Cut with blows" , "Carve with axe" , "Chop (wood)" , "Carve out of wood or stone" , "Shape wood, as with an axe" .)