Place power in bullet — that should get things motoring! (5,4)
I believe the answer is:
spark plug
'that should get things motoring' is the definition.
'place power in bullet' is the wordplay.
'place' becomes 'park' (parking is a kind of placing**).
'power' becomes 'p'.
'in' indicates putting letters inside.
'bullet' becomes 'slug' ('slug' can be a synonym of 'bullet').
'park'+'p'='parkp'
'parkp' placed into 'slug' is 'SPARK-PLUG'.
(Other definitions for spark plug that I've seen before include "Device screwed into a cylinder head" , "engine component" , "Electrical device fitted in the cylinder heads of an internal-combustion engine" , "Ignition device in an internal-combustion engine" , "Agent of ignition" .)