One issue to be aware of with duo props is that if you catch a piece of debris or stick between the conter rotating props, that will run the risk of chipping a gear tooth, and a relitatively expensive repair (usually a new leg). I caught a 1.5 inch stick between the props at idle. A few weeks later the inboard would not turn over. (remember that these engines shift in the lower unit, like an outboard, and are not as robust as the inboard transmissions). Further inspection revealed ground up gear teeth. Bob Austin