Yanmar 6LPA-STP2 315HP Inboard Diesel Marine Engine
Retrofitting narrow engine bilges on fast sport cruisers, this Yanmar 6LPA-STP2 turbo engine turns an OHC 24-valve 4.164L block at 3800 RPM, generating 315 HP and 80 Amps charging across an 899-lb compact footprint.
- OHC 24-valve head optimizes airflow efficiency
- 899-lb dry weight sharpens boat acceleration
- Mechanical direct injection ensures rugged reliability
- Closed-loop heat exchanger stops saltwater scaling
$8,502.55
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Rapid planing center consoles and water taxi retrofits requiring a narrow engine footprint can install the Yanmar 6LPA-STP2. Operating up to 3800 RPM max, this 4.164-liter 24-valve overhead cam (OHC) inline 6-cylinder diesel produces 315 horsepower. Direct mechanical fuel injection through a high-pressure pump provides reliable throttle response, while turbocharged intercooled air induction ensures snappy low-end acceleration.
Closed freshwater heat exchanger cooling protects the aluminum and iron engine metallurgy from raw saltwater exposure. The engine includes a 12V 80-amp alternator, forced lubrication, and an ultra-light dry weight of 408 kg (899 lbs) without gear.
Engine Performance and Engineering
High-rpm 24-valve OHC design gives this Yanmar inboard engine smooth, car-like responsiveness on the water. Forced oil lubrication protects overhead valve gear, while the narrow block profile allows twin engine installations in tight bilges.
Why Choose the Yanmar 6LPA-STP2 Inboard Marine Engine
Boaters select the 6LPA-STP2 marine engine for its lightweight 408 kg dry mass and high 3800 RPM capability. Delivering 315 horsepower from a narrow 4.164-liter 24-valve block, it fits into compact engine compartments where larger diesels cannot go. Direct mechanical fuel injection and closed heat exchanger cooling ensure long-term reliability.
Warranty and Support
Yanmar backs this engine with a 2-Year Limited Recreational Warranty covering major engine block assemblies against factory defects. provides product-information support before purchase and assistance with order-related questions. A pre-shipment visual inspection confirms the engine crate and documented included rigging items. Review warranty eligibility and current coverage details on before placing your order.
Before Ordering the Yanmar 6LPA-STP2 Inboard Marine Engine
Measure your engine compartment length, width, and overhead clearance for a narrow 4.164-liter inline 6-cylinder block. Confirm your transmission gear ratio, propeller shaft coupling bolt pattern, and fuel line sizes before finalizing your order.
Product Specifications
Yanmar 6LPA-STP2 315HP Inboard Diesel Marine Engine Specs
| Brand | Yanmar |
|---|---|
| Full Model SKU/Code | 6LPA-STP2 |
| Country of Origin | Japan |
| Engine Family/Series | 6LPA Series High-Speed Performance Diesel |
| Engine Type / Configuration | Inline 6-Cylinder, 24-Valve, 4-Stroke, Overhead Cam (OHC) Marine Diesel |
| Fuel Type | Marine Diesel |
| Displacement | 4.164 Liters / 4164 cc |
| Horsepower Output | 315 HP / 232 kW (At Crankshaft) |
| Full Throttle RPM Range | 3800 RPM |
| Aspiration / Induction System | Turbocharged with Intercooler |
| Fuel Injection System | Direct Injection with Mechanical High-Pressure Injection Pump |
| Bore x Stroke | 94.0 mm x 100.0 mm |
| Compression Ratio | 15.8:1 |
| Cooling System Method | Fresh Water Closed Loop Heat Exchanger with Raw Water Sea-Loops |
| Alternator Output | 80 Amps / 12 Volts Base Setup |
| Recommended Fuel Grade | Diesel Fuel No. 2-D, Cetane Rating Min 45 |
| Emission Compliance | EPA Tier 2, IMO Tier I, RCD 1 Compliant Historical Framework |
| Dry Weight | 408 kg / 899 lbs (Excluding Marine Gearbox) |
| Application | Fast sport cruisers, water taxi hull retrofits, rapid planing center consoles, and recreational fishing platforms requiring narrow footprint inline arrays (28-42 ft hulls) |
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