Abstract: A self powered, handlebar operated, earth cultivating machine having a worm gear engine drive and a transversely extending, soil engaging rotating tine wheel is provided with a pair of ground engaging traction wheels spaced therebehind and a sprocket and chair drive train coupled between the tine wheel and each of the traction wheels for driving the latter to selectively propel or brake the machine in accordance with the traction created by the tine wheel with the tilled soil. The worm gear and chain drive train cooperate to lock the traction wheels into a constant driving relationship with the tine wheel in a manner to automatically compensate both for excessive forward thrust produced by the latter in hard soil and for insufficient thrust created thereby in soft soil whereby to eliminate lurching and stalling of the machine and achieve especially smooth, consistent tilling operation.