Sierra International 18-2412 Engine Coupler The Sierra 18-2412 Engine Coupler is interchangeable with the following: Mallory 9-72503, Mercruiser 18311A17, 861523A9, 8M0098795, 18309A2, 812964A2, 18311A2. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Engine Coupler Meets or exceeds the original equipment quality Sierra part number: 18-2412 Interchangeable with the following: Mallory 9-72503, Mercruiser 18311A17, 861523A9, 8M0098795, 18309A2, 812964A2, 18311A2