If engine fails before Vr:

CHOP (the power) and STOP (apply brakes)

You should be just as prepared to abort as you are to take off—always keep your hand on the throttle during takeoff and be prepared to yank it back. If the engine is running rough or there is any other anomaly, abort the takeoff. At the halfway point of the runway, you must have a minimum of 71% of the speed at which you will lift the nose wheel on takeoff or it’s a definite abort (If you rotate at 60 KIAS, you must have 42 KIAS at the runway midpoint).