Yamaha Outboards 300HP | LF300ECB: Counter-Rotation Power for Elite Specialty Vessels with 35-inch Transoms

For the most demanding offshore applications, the Yamaha LF300ECB outboard motor delivers uncompromising power and precision.

This 300HP V6 4-stroke engine is uniquely designed as the counter-rotation (left-hand) partner for multi-engine installations on boats that specifically require an extra-extra-long (35-inch) shaft. This ensures optimal propeller submersion and maximum thrust on vessels with exceptionally high transoms.

Featuring Yamaha’s highly responsive Digital Electronic Control (DEC) “drive-by-wire” throttle and shift, the LF300ECB provides 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), offering an adaptable and powerful solution for the largest, most specialized offshore fishing boats, commercial vessels, and multi-engine luxury cruisers.

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Why the Yamaha LF300ECB is Essential for Massive, Multi-Engine, High-Transom Rigs

The Yamaha LF300ECB is a specialized and technologically advanced outboard at the pinnacle of marine propulsion for the largest recreational and commercial vessels. Its unique combination of counter-rotation and an extra-extra-long 35-inch shaft is paramount for maintaining superior propeller bite and boat stability, especially in the most challenging offshore conditions where very large boats with high freeboard operate. When precisely paired with a standard rotation F300ECB, this configuration effectively cancels out propeller torque, dramatically improving steering ease, straight-line tracking, and overall vessel 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 and specialized vessel.

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Key Features & Benefits: Commanding the Deep with Ultimate Precision and Balanced Thrust

Let’s explore the groundbreaking technologies and robust engineering that make the LF300ECB an industry leader for high-performance, multi-outboard setups on the largest, high-transom boats.

Potent 4.2L Big-Bore V6 for Unrivaled Output

At the very heart of the LF300ECB 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, resulting in significantly more power and torque without increasing outer engine dimensions. This design also contributes to lighter weight, superior cooling, and reduced internal friction, all of which 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 LF300ECB 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 LF300ECB is designed for seamless integration with Yamaha’s optional Helm Master EX® boat control system. While the LF300ECB 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.

Extra-Extra-Long (35-inch) Shaft for Deep-Draft Vessels

The 35-inch (897mm) shaft length of the LF300ECB is purpose-built for boats with the highest transoms, where standard or even ultra-long shafts fall short. This extended shaft ensures the propeller remains deeply submerged, minimizing ventilation and cavitation in the most demanding conditions. This results in:

• Maximized Propeller Bite: Consistent thrust and efficiency, even when operating in heavy seas, ensuring optimal performance from your multi-engine propulsion system.
• Superior Stability: Enhanced handling and reduced porpoising by keeping the propellers securely in the water, crucial for large, high-profile boats.
• Specialty Fit: Ideal for custom-built offshore fishing vessels, specific commercial boats, and multi-engine configurations that demand this extreme shaft length.

Precision Counter-Rotation for Enhanced Balance

The LF300ECB’s left-hand (counter-clockwise) propeller rotation is paramount for multi-engine configurations. When precisely paired with a standard right-hand rotation F300ECB, 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 very large vessel.

Exceptional Fuel Efficiency for Extended Range

Despite its commanding power, the LF300ECB 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 LF300ECB 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 LF300ECB 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 LF300ECB 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 LF300ECB 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 LF300ECB – Extra-Extra-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: E: 897 mm (35.3 inch) – This 35-inch extra-extra-long shaft length is specifically for boats with exceptionally high transoms, ensuring maximum propeller submersion.
• Dry Weight: 273 kg (602 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 F300ECB 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 LF300ECB’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 LF300ECB.
• 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 LF300ECB Advantage

The Yamaha LF300ECB is more than just a powerful outboard; it is a sophisticated, precision-engineered component for the most demanding multi-engine boat systems on vessels requiring exceptional shaft length. It embodies Yamaha’s legacy of uncompromising quality, advanced engineering, and unwavering reliability. With its potent 300HP, advanced Digital Electronic Control, extra-extra-long 35-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 for their most challenging marine endeavors.

Ready to experience the confident power and precision control of the Yamaha LF300ECB 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!