Let me start by saying--whoever designed those tillers, must have had a fiendish "bent" in their thinking processes!
The throttle control cable seems backwards in its operation. The forward-back motion seems to change its self just about the time ya get it all figured out, it runs over yer foot, or grinds through the shed wall! There are two curved handles to control motion, and just about time ya get it figgered out what each one does--they seem to switch their tasks, and there goes the wife's petunia patch, freshly dug up!
I repaired one for a friend, who had used it until the mice ate the charging diode, and bit off some wires and built a nest in the flywheel. I delivered it this evening. He started it up, moved a lever, and promptly knocked over part of his stone wall! Fiendish, i say!