Yamaha Lower Unit Assy - 6FN-45300-03-NA. The Yamaha Lower Unit Assy - 6FN-45300-03-NA is meticulously designed to deliver superior performance and reliability for your Yamaha outboard motor. This lower unit assembly ensures a perfect fit and optimal functionality, significantly enhancing the overall efficiency of your marine engine. Constructed from high-quality materials, it is built to endure the harshest marine conditions, providing long-lasting durability and consistent performance.. Experience smooth and efficient power transmission with the Yamaha Lower Unit Assy - 6FN-45300-03-NA, which minimizes drag and maximizes thrust. This results in improved fuel economy and a smoother ride on the water. Trust in Yamaha's commitment to quality and innovation with this lower unit assembly, ensuring your boat performs at its peak in all conditions, delivering a reliable and enjoyable boating experience.. 6FN-45300-03-NA - LOWER UNIT ASSY