Cummins B4.5 Marine Engines

Built for operators who value dependable diesel performance, the Cummins B4.5 Series delivers efficient propulsion, compact installation, and lasting reliability across a wide range of marine applications.

Compact Dimensions. Serious Capability.

Not every vessel requires high horsepower, but every vessel depends on reliable propulsion. The Cummins B4.5 Series was developed for builders and owners seeking a compact marine diesel platform that maximizes available engine room space while delivering the durability expected from one of the world’s most respected diesel manufacturers. Its four-cylinder design combines responsive low-speed torque with electronically controlled fuel delivery to provide smooth acceleration, economical operation, and dependable day-to-day performance. Whether installed aboard coastal cruisers, commercial fishing boats, pilot craft, utility vessels, or repower projects, the B4.5 demonstrates how intelligent engineering can deliver substantial capability from a remarkably compact engine platform.

Explore the Cummins B4.5 Series

* Cummins B4.5 150
* Cummins B4.5 230
* Cummins B4.5 250

Designed to Maximize Every Operating Hour

Marine engines often spend far more time maintaining steady cruising speeds than operating at full throttle. The Cummins B4.5 Series is engineered with this operational reality in mind, combining efficient combustion, dependable electronic engine management, and a durable mechanical design that supports long service intervals and consistent performance. Its balance of compact packaging, fuel efficiency, and dependable torque makes it a practical propulsion solution for operators seeking confidence on the water without unnecessary complexity.