Yanmar 4PHE Marine Diesel Engine The Yanmar 4PHE is a robust, inboard diesel engine engineered for reliable propulsion in marine applications, powering a wide range of vessels with dependable performance in demanding saltwater environments. Key technical specifications underscore its engineering excellence: Featuring a 3,119 cm³ (3.12-liter) displacement in a 4-cylinder in-line configuration, the 4PHE employs a 4-stroke cycle with a bore of 95 mm and stroke of 110 mm. It delivers 80 DIN hp (58 kW) at 2,900 rpm, utilizing efficient diesel fuel for optimal combustion. The water-cooled system ensures thermal management during extended operations, complemented by a direct exhaust setup and corrosion-resistant cast-iron block. Weighing approximately 350 kg, its compact design facilitates seamless integration into standard inboard mounting configurations, with reduction gear compatibility for versatile drive systems. Tailored for marine use, the 4PHE excels in durability and reliability, boasting a service life exceeding 10,000 hours with routine maintenance. Vibration-dampening mounts minimize noise and crew fatigue, while its saltwater-resistant components guard against corrosion in harsh conditions. Fuel efficiency is a standout, balancing the 3.12-liter displacement with economical diesel consumption to lower operational costs without compromising power. Performance-wise, the 4PHE provides consistent torque for steady cruising, making it ideal for displacement hulls requiring reliable low-to-mid-range output. Its simple 4-cylinder architecture allows easy access for servicing filters, belts, and fluids, reducing downtime. This engine suits trawlers, cabin cruisers, small yachts, and workboats, where longevity and straightforward retrofits are paramount. Though an era-defining design from the 1980s–1990s, the Yanmar 4PHE remains a trusted choice for classic vessels prioritizing robust, emission-compliant performance in marine propulsion.