Mercury 300HP F300 4-Stroke XL Shaft Outboard Motor F300 XL CMS DS HD

Mercury 300HP F300 4-Stroke XL Shaft Outboard Motor 

Mercury 300HP F300 4-Stroke XL Shaft Outboard Motors are a masterpiece of marine engineering designed to redefine your expectations of power and refinement. Whether you are repowering a high-performance vessel or outfitting a new adventure, this V8 powerhouse delivers a blend of legendary performance and sophisticated comfort that is simply unmatched. Built on a massive 4.6-litre V8 powerhead with a quad-cam design, engineered to provide remarkable "slingshot" torque for rapid hole shots and instant midrange response. Remarkably, it remains the lightest in its class by at least 10 pounds (approx. 4.5kg), giving your boat a class-leading power-to-weight ratio for improved agility and efficiency.

This XL model features a 25-inch (635mm) shaft, making it perfectly suited for a wide variety of larger offshore and coastal craft.

Mercury 300HP F300 4-Stroke XL Shaft Outboard Motor  Key Features

• V8 Muscle with Class-Leading Weight: The 4.6L V8 powerhead features a quad-cam design that delivers remarkable "slingshot" torque, especially in the mid-range. It is the lightest in its class by at least 10 pounds (approx. 4.5kg), ensuring a superior power-to-weight ratio for your vessel.
• Adaptive Speed Control: An industry-first feature that automatically maintains your engine's RPM despite changes in load or conditions—such as rough water, tight turns, or tow sports—eliminating the need for constant throttle adjustments.
• Quieter by Design: Featuring a large muffler and a sophisticated, vibration-dampening cowl design, these outboards deliver a smoother and quieter ride than any competing engine at any speed.
• Digital Throttle & Shift (DTS): Experience silky-smooth shifting and instantaneous throttle response for total command of your boat. This system also integrates with Active Trim, which automatically optimises your trim for better performance and fuel economy.
• Intelligent Battery Management: To keep your electronics running all day, the engine automatically increases idle RPM when it senses low voltage, boosting the 85-amp alternator's output to replenish your charge.
• Simplified Maintenance: A unique top-cowl service door allows for quick oil level checks without removing the entire cowl. Inside, you will find colour-coded touchpoints and QR codes that link directly to maintenance instructions.
• Advanced Range Optimisation: Go further on every tank with intelligent features that automatically adjust fuel delivery for optimised cruising efficiency.
• Personalised Style: Match your boat’s aesthetic with four engine colour options—traditional Phantom Black or three premium shades of white (Cold Fusion, Warm Fusion, and Pearl Fusion). You can further customise with accent panels available in five distinct colours.

Technical Specifications

Horsepower: 300 HP

Engine Type: V8 (32-valve, DOHC) 

Displacement: 4.6L (279 cu in) 

Full Throttle (WOT) RPM: 5200–6000 

Shaft Length: Extra Long (XL) (25 in / 635mm) 

Dry Weight: 239kg (Lightest-version model)

Alternator Output: 85 amp (1071 watt)

Warranty: Backed by a three-year limited warranty and an industry-exclusive three-year corrosion warranty.

Visit us at Morgan Marine to discover how the Mercury 300HP V8 XL can transform your boating experience to the next level.

Mercury 300HP F300 4-Stroke XL Shaft Outboard Motor  FAQs

What makes the 300HP V8 engine design special?

The 4.6L V8 powerhead features a quad-cam design that is engineered to deliver legendary performance. It provides instantly responsive "slingshot" torque, particularly in the midrange, and helps your boat get on plane quickly.

What does "XL Shaft" mean for this model?

The "XL" indicates an Extra Long shaft length of 25 inches (635mm), which is a common requirement for many larger offshore and coastal vessels.

Is this engine heavy for its power output?

Quite the opposite. These outboards are "light but mighty," being at least 10 pounds (approx. 4.5kg) lighter than any competing engine in their class. This class-leading power-to-weight ratio ensures less weight on your transom while providing massive power.

How does "Adaptive Speed Control" help me? 

This industry-first feature maintains your engine's RPM without you needing to make frequent throttle adjustments. Whether you are dealing with rough water, tight turns, or tow sports, the engine performance remains steady regardless of changes in load or conditions.

What are the benefits of Digital Throttle & Shift (DTS)?

Available DTS controls provide silky-smooth shifting and an immediate throttle response, offering you effortless handling and complete command. This system also integrates with Active Trim, which automatically optimises your trim for better performance and fuel efficiency.

Can I monitor my engine data on my smartphone? 

Yes, via VesselView Mobile. This app provides personalised access to engine data, notifications, warnings, and maintenance reminders directly on your mobile device.

How does the engine manage battery power?

The engine features All-Day Power management. If it detects low battery voltage while you are trolling or running electronics, it automatically increases idle RPM to boost the 85-amp alternator's output and replenish your charge.

How has Mercury made routine maintenance easier?

Routine maintenance is simplified with an exclusive top cowl service door, which allows you to check and top up your oil without ever having to remove the entire cowl. Inside, you will find colour-coded touchpoints and QR codes that link directly to maintenance instructions.

What warranty coverage is provided?

For your peace of mind, every Mercury FourStroke is backed by a three-year limited warranty and an industry-exclusive three-year corrosion warranty.

Can I customise the look of my outboard?

Absolutely. In addition to our traditional Phantom Black, you can choose from three shades of white: Cold Fusion, Warm Fusion, or Pearl Fusion. You can further personalise your motor with accent panels available in five different colours to match your boat's aesthetic.

If you have any further technical questions or wish to discuss a bespoke installation, please contact the team at Morgan Marine today.