Mercury SeaPro 300hp V8 – heavy-duty 4.6L commercial outboard with Advanced MidSection (AMS)

Mercury’s SeaPro 300hp V8 AMS is engineered to meet the challenges of daily commercial use, delivering high horsepower with unparalleled durability and smoothness. At its core lies a 4.6-liter V8 powerhead – boasting one of the largest displacements in its class – specifically tuned for commercial duty. This means more power with less strain: The SeaPro 300 generates ample torque at lower RPM, allowing you to push heavy loads or large boats without overstressing the engine. Whether you’re ferrying passengers, hauling cargo, or patrolling offshore waters, the 300 SeaPro provides confident performance day in and day out.

One standout feature of this model is Mercury’s Advanced MidSection (AMS) technology. The SeaPro 300 AMS employs an advanced midsection mounting system that cradles the V8 powerhead and absorbs vibrations. The result is a drastic reduction in the vibration and noise transmitted to the boat – improved comfort for the crew and extended longevity for the engine and hull. Operators will experience noticeably smoother running at all speeds – a rare luxury in the commercial realm. Additionally, the heavy-duty gearcase on the 300 SeaPro is built to endure where others cannot: It’s validated for three times the lifespan of a standard recreational gearcase. With robust gears and bearings and a hydrodynamic design, this lower unit handles high torque output and continuous operation with ease, exactly what commercial service demands.

From an operational perspective, the SeaPro 300hp is designed for efficiency and reliability. The engine is calibrated to perform on regular unleaded fuel and comes equipped with Mercury’s Idle Charge battery management – at idle, the alternator automatically ramps up output to keep batteries charged for critical electronics. The 85-amp alternator ensures you have ample power for lights, navigation, pumps, and more – crucial for workboats with significant electrical needs. Maintenance intervals are extended and routine checks simplified via the top-cowl oil access door, meaning less time on the dock and more time on the job. All these factors contribute to a lower total cost of ownership and more productive hours on the water.

• Ideal use cases: Mid- to large-sized commercial boats (approximately 7–9 meters), such as water taxis, patrol boats, and heavy-duty fishing vessels, that require a balance of high power and all-day reliability. The SeaPro 300 really shines on vessels that face tough conditions daily and need an engine that can handle the pressure.
• Recommended for: Professional operators – from maritime agencies and tour boat companies to commercial fishermen – who demand a smooth yet powerful engine for daily operations. The Mercury SeaPro 300hp AMS stands out where durability, easy maintenance, and strong performance are paramount, providing dependable power for every task from patrolling and passenger transport to aquaculture work and offshore fishing.