Though I agree this item seems to fall along the uses of some sort of throttle, pull mechanism, I don't think it would be off a lawn mower or any such yard device. Within the relatively modern age of such equipment there are other cheaper substitutes for making the same mechanism, such as plastic and pot metal. Being made of brass I would guess it to be something that was used on a device much older. Or at least a something that was a part of heavy equipment where strength and reliability is a must. What that would be I wouldn't have the slightest.