Description
Yamaha F115JB – 115-HP Jet Drive Outboard Engine
The Yamaha F115JB Jet Drive is a high-performance four-stroke outboard engineered for shallow-water precision and adaptability. It eliminates the conventional propeller in favor of a jet pump, giving boaters access to areas typically off-limits—like shoals, rocky flats, sandbars, and rapids—without risking damage to the propulsion system.
Engine & Design Highlights
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Powered by a 1.8-liter (1,832 cc) inline-4 engine, utilizing a dual overhead cam (DOHC) layout and 16 valves for enhanced airflow and performance.
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Despite being labeled “115 HP,” it delivers around 80 HP at the pump, reflecting the difference between crank and jet thrust ratings in jet-drive systems.
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Incorporates long-tube intake tracks, designed to boost low and mid-range torque for stronger acceleration (“hole-shot”) performance.
Key Specifications
| Specification | Detail |
|---|---|
| Engine Type | 1.8 L inline-4, DOHC, 16-valve |
| Jet Thrust Output | ~80 HP at pump (at ~5,800 RPM) |
| Full-Throttle RPM Range | ~5,000 – 6,300 RPM |
| Shaft Length | 25″ (X-Long) |
| Weight (w/ jet unit) | ~377 lbs (171 kg) |
| Steering Control | Remote mechanical |
| Starter | Electric |
| Alternator Output | ~35 A at wide-open throttle |
| Fuel System | Electronic Fuel Injection (EFI) |
| Tilt & Trim Range | Tilt: ~70°; Trim: –4° to +16° |
| Corrosion Protection | YDC-30 alloy + Phaze Five™ multi-layer finish |
| Warranty | Approx. 2 years (pleasure-focused programs) |
| Recommended Fuel | 87 octane |
| Applications | Shallow, rocky, or fast-changing water environments |
Performance & Advantages
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Superb Shallow-Water Handling
The jet drive allows the boat to navigate waters that would otherwise damage propellers or lower units. -
Strong Acceleration & Responsiveness
Long intake tracks and DOHC design produce brisk mid-range torque, delivering a smooth and powerful start and quick throttle response. -
Low Maintenance Convenience
Features like the freshwater flush system simplify upkeep and help extend engine life. -
Built for Durability
Yamaha’s proprietary YDC-30 alloy and Phaze Five™ anti-corrosive coating provide rugged protection against salt, moisture, and wear. -
Balanced Design
The setup remains relatively light and compact while delivering ample power—making it ideal for mid-sized boats in tough shallow environments.
Ideal Applications
The F115JB Jet Drive is perfect for:
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Deck boats and deep-V hulls operating in shallow or rocky rivers
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Adventure and recreational boats in tidal flats, delta zones, or sandbar-prone areas
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Vessels dedicated to white-water, flats fishing, or remote water access where prop clearance is critical
Summary
The Yamaha F115JB is a purpose-built, jet-drive outboard that blends Yamaha’s engineering with specialized design for adventurous boating. Its DOHC engine with 16 valves and EFI offers efficient power delivery, while the jet-driven propulsion ensures you can traverse challenging environments effortlessly. Lightweight, well-protected from corrosion, and full of thoughtful features like remote steering and freshwater flushing, this engine brings reliable power where traditional props can’t go.
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