Meet the newest members to Mercury's FourStroke Family

What if you could hang a lighter, lower-horsepower FourStroke outboard on your transom without sacrificing speed, hole shot, driving experience or sheer pulling power? What if that outboard also delivered increased fuel savings, hassle-free maintenance and rugged reliability?

Lightweight / Fuel Efficient

Mercury’s world-renowned engineering team has packed incredible power into these lighter, compact four-cylinder single-overhead-cam engines. The 115hp weighs 20 pounds less than its closest four-stroke competitor, making it the world’s lightest low-emissions outboard in its power range. The result is greater acceleration, improved fuel efficiency and a serious repower option for older boats not designed for heavier four-strokes.

Powerful and Efficient

Less weight and high displacement mean Mercury’s new 75 – 115 FourStrokes generate abundant torque and immediate power. Because they don’t have to work as hard as heavier engines or those with lower displacement, these engines make boats plane faster, accelerate better and provide optimal fuel efficiency at cruising speed. With these outboards in your arsenal, you can beat your competition to the fishing grounds and keep casting long after others head for home.

Low Friction

Mercury engineered these FourStrokes to rank among the lowest-friction engines on the water. Specialized crankshaft oil dams and bearings minimize the amount of oil left suspended in the crankcase, so the crankshaft encounters minimal resistance. As friction is reduced, less power is needed to run the engine – leaving more power available to run the boat efficiently. The valve train is low-friction and contributes to the efficiency of the total package.

Quiet and Smooth

Customers tell us they can barely hear these outboards running — especially at idle — because Mercury successfully reduced noise and vibration in these next-generation FourStrokes. The result is an ultra-smooth ride and the ability to enjoy nature without overpowering it.

Sound-Absorbent Cowl

The tightly sealed cowl is lightweight, compact and thermo-bonded to keep noise inside. The top-mounted throttle body lets Mercury technicians fine-tune intake noise for a more pleasing sound.

Focused Mounts

Mercury’s exclusive Focused Mount System significantly reduces vibration, which in turn increases engine durability and life. Equally important, it provides a smoother, more enjoyable driving experience.

Easiest to Maintain

Save money and time with these incredibly easy-to-maintain FourStrokes. Every inch of these engines is designed with ease of maintenance in mind, including an exclusive lifetime maintenance-free (yes, you read that right!) valve train.

No-Spill Oil Change

A convenient drip tray beneath the automotive-style, spin-on oil filter catches any residual oil in the system after the sump is drained. You can change the oil faster with no muss, no fuss.

EZ Change Fuel Filter

No tools are needed to change the filter; an easy-access bracket holds it securely while you pop it out with just two fingers. Swapping for a fresh filter takes less than a minute.

Maintenance-Free Valve Train

Thanks to “Lash for Life” valve train technology, available exclusively on Mercury’s FourStroke outboards of 75hp and higher, you’ll never have to take your outboard to a technician for an expensive valve-lash adjustment. Unlike other four-strokes, these truly are maintenance free.

DIY Instructions

When routine service is needed, it’s nice to have the instructions posted where you can immediately find them. Use your smartphone to scan the QR code on the maintenance label under the cowl and it will link you to a Mercury mobile site with handy “how to” online videos.

Repower and Re-energize

A new Mercury FourStroke can re-energize your boat by providing better acceleration, all-out performance and precise maneuverability. The 75-115 FourStrokes are engineered to deliver two-stroke-grade power-to-weight ratios. That makes them a great fit — even for older boats with transoms that can’t handle the added weight of older four-stroke engines. If your boat is already rigged for Mercury just bolt it on and go.

Command Thrust

The 90hp and 115hp FourStrokes are available with Mercury's mighty Command Thrust package. The larger “CT” gearcase and 2.38:1 gear ratio, paired with Mercury’s V6-class bigger-diameter propellers, provides greater acceleration, better handling, awesome maneuverability, and superior stopping power.

HP/kW 75 / 55.2
Full throttle RPM 4500-5500
Cylinder Configuration I-4
Displacement (CID / CC) 126
Displacement (L) 2.1
Bore and Stroke (in / mm) 3.5 x 3.2in
90 x 81mm
Fuel Induction System Computer controlled Sequential Multi-Port Electronic Fuel Injection (EFI)
Ignition SmartCraft ECM 07 Digital Inductive
Alternator Amp 35 amp / 441 watt
Cooling System Water-cooled with thermostat
Starting Smart Start Electric
Gearcase Ratio 2.07:1
Gear Shift F-N-R
Gearcase Options Standard
Steering Dual Cable Mechanical, Hydraulic, or Big Tiller
Trim System Power Tilt
Power Trim
Exhaust System Through prop
Recommended Fuel Unleaded Regular 87 Octane Minimum (R+M/2) or 90 RON 10% Ethanol Maximum
Engine Protection Operator Warning System SmartCraft Engine Guardian
Compatible with Smartcraft Digital Technology Yes
Shaft Length 20 in (508 mm)
Dry Weight * Lightest model available 359lbs / 163kg

FourStroke 75 - 115 HP Engine Tests

There are currently no engine tests for this product line.

FourStroke 75 - 115 HP Resources

Buy the Books

You can order all available Mercury literature online or through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

  • Operation, Maintenance and Warranty Manuals
  • Parts Manual
  • Service Manual
Purchase a Manual
Request a Brochure

Request printed brochures by mail or download as an electronic PDF.

Request a Brochure

FourStroke 75 - 115 HP Boat Brands

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Command Thrust

Need more muscle to move your boat? The 90hp and 115hp FourStrokes are available with Mercury’s mighty Command Thrust package. The larger “CT” gearcase and 2.38:1 gear ratio, paired with Mercury’s V6-class bigger-diameter propellers, provides greater acceleration, better handling, awesome maneuverability, and superior stopping power.

Bigger Footprint

The larger “CT” gearcase creates a bigger footprint in the water, which provides more leverage to control your boat. The larger torpedo, combined with a bigger-diameter prop, can lift a heavy boat onto plane more easily and hold it there at lower speeds without impacting top speed.


Do you like to boat offshore even through you’re not in the market for a big boat? For the first time, Mercury is offering a 115hp FourStroke with left-hand rotation. Two of these mid-range monsters on your transom provide the maneuverability and get-home safety of higher-horsepower twins at a price that’s easier on your wallet. Unlike competitive dual 115hp engines, dual 115 Mercury FourStrokes are Command Thrust models, which swing V6-class propellers, such as Enertia series to deliver improved acceleration and better boat control in rough water.

Gearcase Selector

Note: The above recommendations should be considered guidelines, not absolutes. Proper boat setup is always dependent on the individual boat model, engine height, propping, and normal running loads. In general, a Command Thrust model provides more lift than a standard model, and will perform best on boats that typically run “wet” (boats that typically operate with more running surface in contact with the water while on plane). As such, there will be exceptions to the above recommendations. Your local Mercury dealer can help you select the best model to maximize your boat’s performance.

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