This has already been asked before but the answer on the ohter one wasn't very clear so I'll answer this one.
It does power up Outrage, but it would work with each use of Outrage, not each hit. The basic rule for Metronome is that the move is only powered up if spammed, each time getting more powerful, but it only inreases that power when a PP (Power Point) is deducted for the use of the move.
