Cummins 5.9 marine engine deliver dependable power and rugged performance for a wide range of marine vessels. Featuring a robust inline-six design, these engines use mechanical or electronic fuel systems—depending on the model year—to provide precise fuel delivery and efficient combustion. Their cast-iron blocks, forged internals, and efficient cooling systems enable them to endure the continuous loads and harsh conditions of marine environments. Known for strong torque at low RPMs, easy maintenance, and long service life, the Cummins 5.9 excels in both commercial and recreational marine applications. These engines combine mechanical simplicity with proven engineering to deliver consistent, seaworthy performance.