Yamaha Outboards 300HP | LF300UCB: Counter-Rotation Power for Elite High-Transom Vessels

Command the most challenging offshore environments with the Yamaha LF300UCB outboard motor.

This 300HP V6 4-stroke engine is precisely engineered as the counter-rotation (left-hand) partner for twin or triple-engine installations on boats demanding an ultra-long (30-inch) shaft for optimal propeller submersion.

Featuring Yamaha’s highly responsive Digital Electronic Control (DEC) “drive-by-wire” throttle and shift, the LF300UCB ensures incredibly smooth and precise handling.

While its primary steering is remote hydraulic, it’s fully compatible with Yamaha’s versatile Helm Master EX® system (with the addition of necessary steering components), providing an adaptable and powerful solution for the largest offshore fishing boats, multi-engine luxury cruisers, and high-performance center consoles.

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Why the Yamaha LF300UCB is Indispensable for Large, Multi-Engine High-Transom Rigs

The Yamaha LF300UCB is a specialized and technologically advanced outboard designed for seamless operation on the grandest recreational vessels. Its unique combination of counter-rotation and an ultra-long 30-inch shaft is crucial for maintaining optimal propeller bite and boat stability, especially in rough offshore conditions where larger boats with high freeboard operate. When precisely paired with a standard rotation F300UCB, this configuration effectively cancels out propeller torque, dramatically improving steering ease, straight-line tracking, and overall boat control. The advanced Digital Electronic Control (DEC) and Helm Master EX® compatibility then elevate this precise balance with intuitive “drive-by-wire” throttle/shift and the potential for advanced joystick control and autopilot features, transforming the experience of handling a truly grand vessel.

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Key Features & Benefits: Powering Your Command with Digital Precision and Balanced Thrust

Let’s explore the groundbreaking technologies and thoughtful engineering that make the LF300UCB an industry leader for high-performance, multi-outboard setups on large, high-transom boats.

Potent 4.2L Big-Bore V6 for Unrivaled Output

At the very heart of the LF300UCB is a formidable 4.2L (4169cc) 60-degree V6 engine. This “big-bore” displacement is achieved through an advanced thermally applied plasma fusion process on the cylinder walls. This innovative process eliminates conventional steel cylinder sleeves. Instead, the cylinder walls are an impressive 60% harder than steel. Consequently, this allows for larger cylinder bores. This means significantly more power and torque without increasing outer engine dimensions. This design also contributes to lighter weight, superior cooling, and reduced internal friction. All these factors enhance both performance and long-term reliability. Therefore, expect immediate, exhilarating power delivery whenever you demand it.

Digital Electronic Control (DEC) for Smooth, Precise Shifts

The LF300UCB features Yamaha’s advanced Digital Electronic Control (DEC) system for both throttle and shift. This “drive-by-wire” technology replaces traditional mechanical cables with electronic signals, providing:

• Silky-Smooth Shifting: Effortless and precise gear changes, enhancing overall driving comfort.
• Responsive Throttle Control: Instantaneous engine response to your throttle inputs, ensuring precise speed management.
• Reduced Rigging Clutter: A cleaner helm and transom area due to the absence of mechanical cables.
• Effortless Multi-Engine Sync: Perfect synchronization in dual or triple engine applications, simplifying operation.

Helm Master EX® System Ready (with Steering Components)

The LF300UCB is designed for seamless integration with Yamaha’s optional Helm Master EX® boat control system. While the LF300UCB typically utilizes a remote hydraulic steering system, it can be upgraded with Yamaha’s bolt-on Digital Electric Steering (DES) to unlock the full suite of Helm Master EX capabilities, including:

• Joystick Control: Unparalleled maneuverability for effortless docking and precise positioning in tight spaces (especially with multi-engine setups).
• Autopilot Functionality: Features like Course Hold, Heading Hold, and Track Point for relaxed, hands-free navigation on long stretches.
• SetPoint™ Modes: StayPoint™, FishPoint™, and DriftPoint™ automatically maintain your boat’s position or heading, revolutionizing fishing, waiting at docks, or holding position in current.
• Pattern Steer: Pre-programmed fishing patterns for precise lure presentation and efficient searching.

This modular system allows you to customize your level of boat control to match your specific needs and budget, providing a truly adaptable and future-proof platform.

Ultra-Long (30-inch) Shaft for Optimal Submersion

The 30-inch (770mm) shaft length of the LF300UCB is specifically engineered for boats with an exceptionally tall transom. This extended shaft ensures the propeller remains deeply submerged, minimizing ventilation and cavitation in rough water. This results in:

• Improved Propeller Bite: Consistent thrust and efficiency, even when operating in challenging sea states, ensuring optimal performance from your multi-engine setup.
• Enhanced Stability: Better handling and reduced porpoising by keeping the props securely in the water.
• Ideal Fit: Perfect for custom-built offshore vessels, very large center consoles, and specialized applications designed for this transom height.

Precision Counter-Rotation for Enhanced Balance

The LF300UCB’s left-hand (counter-clockwise) propeller rotation is paramount for multi-engine configurations. When precisely paired with a standard right-hand rotation F300UCB, the opposing forces generated by the propellers effectively neutralize each other. This dramatically reduces steering effort, eliminates prop walk, and results in a more stable, balanced, and comfortable ride. It provides superior straight-line tracking and enhanced maneuverability, particularly at low speeds and in reverse, which is crucial when docking or backing down on fish with a large boat.

Exceptional Fuel Efficiency for Extended Range

Despite its commanding power, the LF300UCB boasts outstanding fuel efficiency. Its Precision Multi-Point Electronic Fuel Injection (EFI) system ensures precise fuel metering and optimizes combustion for excellent economy. This intelligent system, combined with friction-reducing micro-textured cylinder walls, delivers superb fuel economy across the entire RPM range. Thus, you can extend your cruising range, spending more time enjoying the water and less time at the fuel dock.

High-Output Charging for Extensive Electronics

Modern, well-equipped boats demand substantial electrical power. The LF300UCB impressively produces up to 70 gross amps of charging power (55A battery charging). This ample output reliably powers your growing array of onboard electronics, including multiple fish finders, sophisticated navigation systems, and other high-demand accessories, ensuring all your critical systems remain fully operational throughout your longest trips.

Smooth, Quiet, and Refined Operation

Yamaha engineers have meticulously refined the LF300UCB for an impressively smooth and quiet boating experience. Engine exhaust gases are strategically routed through a labyrinth of passages and exit via an idle exhaust relief outlet, significantly reducing sound. The design minimizes vibration and noise, creating a more comfortable and enjoyable time on the water, even during extended journeys.

Built for Unwavering Durability and Smart Maintenance

The LF300UCB is inherently built tough to withstand the rigors of heavy use and harsh marine environments. Its advanced cowling drain system efficiently drains any water, protecting crucial internal components. Incoming air routes through a labyrinth of passages that effectively trap and drain water, ensuring maximum reliability. Additionally, the outboard features Thrust Enhancing Reverse Exhaust (TERE), an innovative system that keeps exhaust bubbles away from the propeller below 2500 RPM and when in reverse. This means the prop bites only clean water, resulting in outstanding reverse thrust and control, which is especially helpful when backing down on fish or maneuvering a large vessel in tight spaces.

For ultimate convenience, the LF300UCB includes Yamaha’s exclusive TotalTilt™ Feature. A swift double-tap of the trim button performs a full tilt up or down, making trailering and shallow water navigation incredibly quick. This feature is also handy for propeller changes or docking.

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Technical Specifications (Yamaha LF300UCB – Ultra-Long Shaft, Counter-Rotation, DEC):

• Engine Type: 4-Stroke, 24-Valve, DOHC with VCT, 60-degree V6
• Prop Shaft Horsepower: 300 hp (220.6 kW)
• Displacement: 4169 cm³ (4.2L)
• Bore x Stroke: 96.0 x 96.0 mm
• Full Throttle Operating Range: 5000-6000 r/min
• Fuel Induction System: Electronic Fuel Injection (EFI)
• Lubrication System: Wet Sump
• Engine Oil Capacity: 6.3 L (with filter)
• Alternator Output: 70 A (gross, 55A battery charging)
• Starting System: Electric Starter
• Steering: Remote Control (Hydraulic or optional bolt-on Digital Electric Steering for Helm Master EX)
• Trim Control System: Power Trim and Tilt with TotalTilt™
• Gear Ratio: 1.75:1
• Shaft Length: U: 770 mm (30.3 inch) – This 30-inch ultra-long shaft length is specifically for boats with a tall transom, ensuring proper propeller submersion.
• Dry Weight: 268 kg (591 lbs) – Weight is approximate and depends on specific configuration.
• Propeller Rotation: Counter-clockwise (Left-hand rotation) – Essential for twin/triple engine installations with a standard F300UCB to neutralize torque and improve handling.
• Ignition System: TCI Micro-computer
• Recommended Fuel: Unleaded gasoline (minimum 89 octane)
• Cooling System: Raw-water, thermostatically controlled
• Exhaust System: Through propeller boss (with Thrust Enhancing Reverse Exhaust)
• Controls: Digital Electronic Controls (DEC) – Required for full functionality and Helm Master EX compatibility.

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Optimize Your Rig with Genuine Yamaha Accessories:

To truly unlock your LF300UCB’s full potential in a multi-engine setup, consider integrating these genuine Yamaha accessories:

• Yamaha Helm Master EX® System Components: Explore joystick control, autopilot, and SetPoint™ features by adding the necessary Helm Master EX components, including the bolt-on Digital Electric Steering for full integration.
• Yamaha CL5 or CL7 Digital Displays: These touchscreen displays provide comprehensive engine data, navigation, and seamless control for Helm Master EX features.
• Saltwater Series II™ HP Propellers: These high-performance propellers are specifically designed to complement Yamaha’s V6 Offshore outboards. They offer excellent performance and feature the Shift Dampener System (SDS®) for smoother, quieter shifting. Ensure you select a left-hand rotation propeller with the appropriate pitch and diameter for the LF300UCB.
• Yamaha 10-Micron Water Separating Fuel Filter: This external filter provides superior protection against water and contaminants, further enhancing reliability and extending engine longevity.

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Power Your Journey: The Yamaha LF300UCB Advantage

The Yamaha LF300UCB is not merely a powerful outboard; it is a sophisticated, precision-engineered component for the most demanding multi-engine boat systems. It embodies Yamaha’s legacy of uncompromising quality, advanced engineering, and unwavering reliability. With its potent 300HP, advanced Digital Electronic Control, ultra-long 30-inch shaft, counter-rotation, and seamless Helm Master EX® compatibility, it offers an unmatched level of control, convenience, and confidence on the water. It’s the ideal choice for boaters who operate very large, high-transom vessels and demand cutting-edge technology paired with Yamaha’s legendary performance.

Ready to experience the confident power and precision control of the Yamaha LF300UCB for yourself? Contact us today to discuss your specific multi-engine boating requirements and discover how this advanced outboard can transform your time on the water. Get a personalized quote. Or, explore our full selection of Yamaha outboards. Our dedicated team is here to help you find the ideal power solution for your next marine adventure!