Yanmar 6LY3-STP Inboard Diesel Engine – High-Performance 480 HP Marine Power
The Yanmar 6LY3-STP is a premium in-line 6-cylinder, 5.8-liter marine diesel engine delivering an impressive 480 mhp (353 kW) at 3,300 rpm. Designed for commercial vessels, high-speed pleasure craft, and demanding offshore operations, it offers exceptional reliability, outstanding torque, and industry-leading fuel efficiency.
Its mechanical injection system provides robust performance with simple, proven engineering, while Yanmar’s advanced turbocharging ensures strong acceleration and speed across the operating range. Built for long service life, this engine meets EPA Tier 2 and IMO Tier II emissions standards, making it both powerful and environmentally compliant.
Key Features
-
Proven Mechanical Injection – Reliable and easy to maintain with reduced electronic complexity.
-
High Torque Output – Delivers strong acceleration and pulling power for heavy-duty marine applications.
-
Turbocharged Performance – Efficient boost for faster speeds and improved fuel burn rates.
-
Commercial-Grade Durability – Built with Yanmar’s precision engineering for long-term reliability.
-
Compact Design – Ideal for repower projects and vessels with tight engine compartments.
-
Low Emissions Compliance – Meets EPA Tier 2 and IMO Tier II regulations.
Specifications
| Feature | Details |
|---|---|
| Model | 6LY3-STP |
| Power Output | 480 mhp (353 kW) @ 3,300 rpm |
| Displacement | 5.813 L (354.7 cu. in.) |
| Cylinders | 6, in-line |
| Bore x Stroke | 106 mm x 110 mm (4.17 in. x 4.33 in.) |
| Aspiration | Turbocharged & Intercooled |
| Combustion System | Direct injection |
| Dry Weight | Approx. 1,085 kg (2,392 lbs) |
| Dimensions (LxWxH) | 1,567 mm x 746 mm x 780 mm |
| Emission Compliance | EPA Tier 2, IMO Tier II |
| Cooling | Freshwater-cooled with heat exchanger |
| Fuel System | Mechanical fuel injection |
| Alternator | 12V – 80A or optional 24V – 60A |
| Recommended Applications | Commercial vessels, patrol boats, offshore sport fishing, high-speed leisure craft |
Comparison Table – Yanmar 6LY3-STP vs. Volvo Penta D6-480 vs. Cummins QSB6.7-480
| Feature / Model | Yanmar 6LY3-STP | Volvo Penta D6-480 | Cummins QSB6.7-480 |
|---|---|---|---|
| Power Output | 480 mhp @ 3,300 rpm | 480 hp @ 3,500 rpm | 480 hp @ 3,300 rpm |
| Displacement | 5.813 L | 5.5 L | 6.7 L |
| Aspiration | Turbo & Intercooler | Turbo & Intercooler | Turbo & Intercooler |
| Fuel System | Mechanical | Common rail electronic | Common rail electronic |
| Dry Weight | 1,085 kg | ~1,075 kg | ~1,150 kg |
| Emission Compliance | EPA Tier 2 / IMO II | EPA Tier 3 / IMO III | EPA Tier 3 / IMO III |
| Best For | Low electronics, easy service | High-speed leisure & commercial | Heavy-duty commercial |
Meta Description
Yanmar 6LY3-STP Inboard Diesel Engine – 480 HP, turbocharged 6-cylinder marine engine for commercial vessels and high-performance leisure craft. Compare with Volvo Penta D6-480 and Cummins QSB6.7.
FAQs – Yanmar 6LY3-STP
Q1: How much horsepower does the Yanmar 6LY3-STP produce?
It delivers 480 mhp (353 kW) at 3,300 rpm.
Q2: Is this a mechanical or electronic engine?
The 6LY3-STP uses a proven mechanical fuel injection system.
Q3: What vessels is it best suited for?
It’s ideal for commercial vessels, patrol boats, offshore fishing boats, and high-speed leisure craft.
Q4: What emissions standards does it meet?
It complies with EPA Tier 2 and IMO Tier II requirements.
Q5: How does it compare to the Volvo Penta D6-480?
The Yanmar offers mechanical simplicity and serviceability, while the Volvo Penta uses electronic common rail for potentially finer fuel control.
