Ryobi 31s were designed as "throw-away" engines, or so I'm told. It costs more to repair than they're worth. So, some sales & repair centers that get a customer looking to have a Ryobi-powered trimmer repaired, simply offer them a "trade-in" toward the purchase of a "better" unit. The trade-in gets tossed in the back. After they get a load of such "junk", they pay a hauler to cart them to the recycler. That is, unless I happen to come along. For free I'll cheerfully haul away these "junk" Ryobis to be recycled into model airplane engines! This plus yard sales can quickly provide you with a lifetime supply of engines, carbs, etc for a very small investment. Better hurry, though; it looks like these 2-strokes are being phased out.