Mitsubishi S6A‑300‑3 300 HP

The Mitsubishi S6A‑300‑3 is a rugged, medium‑speed marine diesel engine designed for reliable propulsion performance in commercial, fishing, and workboat applications where durability and efficiency are paramount. With a rated output of 300 HP, this inline‑6 engine balances strong torque delivery, fuel efficiency, and long service life — making it well‑suited for vessels that require dependable power under continuous load.

Built by Mitsubishi Heavy Industries, the S6A‑300‑3 reflects the company legacy of quality marine engine engineering. Its water‑cooled, turbocharged design ensures effective combustion and thermal management, resulting in excellent torque characteristics and stable power delivery across a broad range of speeds. The engine features a direct fuel injection system that enhances fuel economy, reduces specific fuel consumption, and supports smooth operation even under variable marine loads.

The S6A‑300‑3 is engineered with robust internal components and heavy‑duty cast‑iron construction to withstand the rigors of marine service. Its inline‑6 configuration provides mechanical balance and minimized vibration, contributing to quieter operation and reduced wear over time. The cooling and lubrication systems are optimized for extended duty cycles, helping to maintain optimal operating temperatures and prolong engine life, even in challenging marine environments.

This engine integrates easily with marine gearboxes, propulsion systems, and control interfaces, allowing flexible installation across a variety of boat designs. Whether used as a primary propulsion engine for fishing vessels, workboats, coastal crafts, or support vessels, the Mitsubishi S6A‑300‑3 delivers a dependable combination of performance, efficiency, and durability that operators can trust.

Backed by Mitsubishi extensive global service and parts support network, the S6A‑300‑3 is supported throughout its lifecycle, ensuring continued operation and ease of maintenance. Its proven design and reliable performance make it a competitive choice for marine operators seeking an efficient and robust diesel propulsion solution.

Technical Specifications

General Engine Data

• Engine Model: Mitsubishi S6A‑300‑3

• Type: 4‑stroke, water‑cooled marine diesel

• Cylinders: 6‑in‑line

• Aspiration: Turbocharged

• Displacement: ~ 18.56 L

• Bore × Stroke: 150 mm × 175 mm

• Compression Ratio: ~ 14.5 : 1

• Fuel System: Mechanical direct injection

• Rated Speed: ~ 1800 – 1900 RPM (varies with rating)

• Rated Output: 300 HP (≈ 224 kW)

• Rotation: Counter‑clockwise (viewed from flywheel)

• Mounting: Marine propulsion mounts

Performance

• Rated Power: 300 HP at rated speed

• Torque: Strong torque suitable for marine propulsion duty

• Designed for continuous load / heavy marine use

Cooling & Lubrication

• Cooling System: Water‑cooled jacket with heat exchanger

• Charge‑Air Cooling: Turbocharger with aftercooling (if fitted)

• Lubrication: Full‑flow oil filtration with oil cooler

• Designed for stable thermal performance under continuous use

Physical Dimensions & Weight

• Approx. Dry Weight: ~ 1800 – 2000 kg (engine only)

• Approximate Dimensions (Engine Block):
  • Length: ~ 2090 mm
  • Width: ~ 1019 mm
  • Height: ~ 1420 mm

• Actual size and weight vary depending on accessory configuration

Systems & Features

• Turbocharging: Single turbo for improved air delivery and efficiency

• Fuel Delivery: Mechanical direct injection for reliability

• Serviceability: Accessible service points for maintenance

• Integration: Compatible with marine gearboxes and control systems

Applications

• Marine propulsion for fishing boats, workboats, tugs

• Commercial vessels requiring moderate power

• Workboats & utility crafts

Key Attributes

• Reliable and durable construction

• Efficient combustion for lower fuel consumption

• Smooth power delivery across operating range

• Proven marine performance support