Mercury 4.6L V8 250 and 300hp FourStroke outboards deliver legendary performance and an all-around elevated boating experience. Reliability. Comfort. Power. Handling. Easy ownership. Flexibility. For any body of water and across a wide variety of boats, every facet of a Mercury FourStroke outboard is engineered to ensure you make the most of your time on the water.

Adaptive Speed Control

The Adaptive Speed Control feature lets you maintain engine rpm despite changes in load or conditions. Climbing large swells is easier. Cruising at low speeds is smoother. Carving out tight turns is effortless.

Easy to Maintain

The exclusive Top Cowl Service Door simplifies routine maintenance, letting you check or add engine oil without removing the top cowl. An hour-based maintenance schedule decal is located under the cowl, providing a quick overview of routine maintenance.

Industry-Exclusive Battery Management Technology

When needed, the idle charge battery management system works for you by monitoring battery voltage and adjusting engine rpm at idle to boost alternator output.

Smooth and Quiet

Featuring a large muffler and a vibration-dampening cowl design, Mercury V8 FourStroke outboards deliver an exceptionally smooth, quiet ride at any speed.

Ample Charging Output

A powerful alternator delivers 85 amps of charging power at wide-open throttle – perfect for keeping onboard electronics running long into the fun.

Exceptionally Smooth & Quiet

The V8 300hp FourStroke outboard is 33% quieter at cruise with 30% less transmitted vibration at idle than the leading four-stroke competitor.

High Displacement

The high-displacement, quad-cam design of the V8 FourStroke powerhead generates serious torque, especially at mid-range, for quick acceleration and exciting speeds.

Light & Compact

The V8 300hp FourStroke outboard is the lightest in the 300hp class by more than 20 pounds. Both V8 models mount on 26-inch centers for easy repowers or new installation on a wide range of boats.

Comfort

With a balanced powerhead and sophisticated, vibration-dampening cowl design, Mercury FourStroke outboards deliver an exceptionally smooth and quiet ride at any speed.

Durability

Premium corrosion-preventive technologies and durable components ensure FourStroke outboards can stand up to the most demanding marine environments.

Compact Design

Ideal for new engine setups or repowers, the slender width of a Mercury FourStroke outboard fits most transoms, including those with narrow engine wells and tight motor spacing.

Efficiency

Explore farther and stay out longer thanks to impressive power-to-weight ratios, intelligent fuel systems and optimized fuel injection (on most models) that maximize performance from every drop of fuel.

Horsepower	300
Alternator Amp/Watt	85 amp (1071 Watt) with Idle Charge
Color	Black / Cold Fusion White / Warm Fusion White / Pearl Fusion White
Smartcraft Compatible	Yes
Displacement (L)	4.6
Dry Weight (Lightest Model)	527 lbs / 239 kg
Engine Type	V8
HP / KW	300 / 221
Recommended Fuel	Unleaded Regular 87 Octane Minimum (R+M/2) or 90 RON 10% Ethanol Maximum
Prop Rotation	RH
Shaft Length	20
Control	RM
Trim and Tilt	PTT