Mercury - V-6 FourStroke Outboards from 175 to 225-HP

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Captain's Report

Mercury V-6 FourStroke boat engine

Mercury’s V-6 FourStroke outboards offer light weight and innovation.

The new 3.4L V-6 employs a large displacement, naturally aspirated powerhead and proven mid-section and drive-system designs. Additionally, the 3.4L V-6 outboards are versatile, offering the option of mechanical or digital controls, hydraulic or power steering, and black or white cowls on FourStroke-branded products, as well as a variety of accent panel colors. This versatility makes the new V-6 an ideal engine for repower applications.


Low-End and Mid-Range Torque


Going hand-in-hand with the considerable displacement of this engine platform is improved low-end and mid-range torque. Mercury says that the new engine platform – which has the largest displacement in the 200-hp outboard class – has 20% more torque than its closest 4-stroke competitor at best cruising speeds. (The Yamaha 200-hp V-6 has 3.3 L displacement and the Yamaha in-line 4 200-hp engine has 2.7 L displacement.) This means that the new Mercury can deliver better hole-shot times than other 4-stroke engines in class, something that both tournament bass anglers and beginning water skiers and wake boarders will appreciate.


Fuel Efficiency


The company calls its calibration system Advanced Range Optimization (ARO) and uses it in conjunction with closed-loop fuel control to adjust the fuel mixture. Mercury has calibrated the engine for maximum fuel-efficiency in the mid RPM ranges, and claims that it is up to 15% more fuel-efficient than its closest 4-stroke competitor.


Bearing sizes and oil flow have been engineered to reduce internal friction and improve overall efficiency, according to Mercury. The company also has expanded its line of Mercury props to accommodate the performance of these outboards.


Light Weight


The 3.4-liter V-6 FourStroke has also shed some pounds over the previous generation of Mercury outboards, on the order of 35 lbs. (16 kg). The lightest available model of all horsepower ratings (meaning the shortest shaft length) weighs 475 lbs. (215 kg). This compares favorably with other V-6 4-strokes from Yamaha, Suzuki, and Honda, which each weigh at least 10 lbs. (5 kg) more.


Mercury V-6 FourStroke outboards
Mercury’s V-6 4-strokes come in Phantom Black (shown) and three shades of white, with a contrasting color accent panel for a hint of personalization.

Quiet Operation


4-stroke outboards have long featured quiet operation as a hallmark, and Mercury says these engines are “unsurpassed” in keeping engine noise and vibration in check. The V-6 design is naturally balanced, and multi-chamber air-intake quiets induction noise, according to the manufacturer. Also, Mercury points out that fuel-injector covers reduce noise, and the cowling is designed to keep engine sounds from reaching the operator.


Major Features



  • An “Idle Charge” battery-management system detects high power draw and increases idle speed to turn the alternator faster. The idea is to help boaters keep their batteries charged when peripheral equipment overtaxes the electrical system. Mercury says that the engine has a “best-in-class" net charging output of 20 AMP at 650 RPM. This is important on a boat equipped with a trolling motor, livewells with pumps working, a large electronics suite, as well as other accessories.

  • The outboards have a compact profile that may simplify multi-engine applications, and mounts on 26” (66 cm) centers. The styling is contemporary and all outboards come in Mercury Phantom Black, while Warm Fusion White, Cold Fusion White, and Pearl Fusion White cowling are now available in the 225-hp and 200-hp models, with accent color panels.

  • A Top Cowl Service Door allows for easier checks of engine oil level. Opened with a single push, the door also places key service and maintenance decals out of sight. Concealed inside this door is also a folding cover carrying handle, to give boaters a handhold when they do need to lift the cowling off these sleek outboards. Getting a look under the bonnet on a regular basis is a good idea and can help boaters spot leaks, corrosion, and other problems earlier, and maybe head off headaches later.

  • Adaptive Speed Control that maintains RPM regardless of load or sea condition changes, which greatly improves the driving experience.


Mercury V-6 FourStroke gear case
Mercury says its gearbox is designed for hydrodynamic efficiency.

Rigging Options


Available with mechanical or digital controls, the V-6 4-stroke outboards add options for new boats and repowering projects. Consumers can choose between standard hydraulic or optional power steering.


200-hp V-6 SeaPro


The Mercury SeaPro 200-hp 3.4L V-6 FourStroke outboard has the company’s largest displacement in its class. It also is the lightest engine in its class and is approximately 25 lbs. (11 kg) lighter than the engine it is replacing. Like all Mercury SeaPro outboard engines, the 3.4L V-6 4-stroke is built for durability and reliability and is calibrated for commercial usage.


Like the 3.4L V-6 175 to 225-hp FourStroke outboards, the new 200-hp V-6 SeaPro outboard features "Advanced Range Optimization/ARO" calibration, which was developed by Mercury engineers to optimize cruise fuel economy. The ECU will adjust fueling automatically when conditions are right to extend range and endurance. It does this so seamlessly that the operator won’t feel or hear it, according to the company.


Mercury 225 FourStroke V-6 Outboard Specifications



    Horsepower: 225


    WOT RPM: 5200-6000


    Engine Type: V-6


    Displacement: 209 CID (3.4L)


    Induction: 24-valves, DOHC


    Starting: SmartStart Electric


    Gear Ratio: 1.85:1


    Alternator: 85 Amp (1071 watt)


    Trim System: Power trim and tilt


    Dry Weight*: 475 lbs. (215 kg)


    Steering: Hydraulic (Standard base), Power (options)


    Shaft Length: 20” (508 mm), 25” (635 mm), 30” (762 mm)


    Colors: Phantom Black, Pearl Fusion White, Warm Fusion White, Cold Fusion White



Mercury 200 FourStroke V-6 Outboard Specifications



    Horsepower: 200


    WOT RPM: 5000-5800


    Engine Type: V-6


    Displacement: 209 CID (3.4L)


    Induction: 24-valves, DOHC


    Starting: SmartStart Electric


    Gear Ratio: 1.85:1


    Alternator: 85 Amp (1071 watt)


    Trim System: Power trim and tilt


    Dry Weight: 475 lbs. (215 kg)


    Steering: Hydraulic (Standard base model), Power (options)


    Shaft Length: 20” (508 mm), 25” (635 mm)


    Colors: Phantom Black, Pearl Fusion White, Warm Fusion White, Cold Fusion White



Mercury 175 FourStroke V-6 Outboard Specifications



    Horsepower: 175


    WOT RPM: 5000-5800


    Engine Type: V-6


    Displacement: 209 CID (3.4 L)


    Induction: 24-valves, DOHC


    Starting: SmartStart Electric


    Gear Ratio: 1.85:1


    Alternator: 85 Amp (1071 watt)


    Trim System: Power trim and tilt


    Dry Weight*: 475 lbs. (215 kg)


    Steering: Hydraulic (Standard base model), Power (options)


    Shaft Length: 20” (508 mm), 25” (635 mm)


    Color: Phantom Black



*lightest available model