Fire up (6)
(Other definitions for rev that I've seen before include "Minister" , "serviceman?" , "Clergyman, or woman (abbr)" , "Cleric" , "Run (engine) quickly" .)
'fire up' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ignite that I've seen before include "Burn" , "Catch fire; provoke" , "Cause to catch fire" , "Swan constellation" , "Torch" .)