Mercruiser 8.1S Horizon Marine Gas Engine

On Sale Mercruiser 8.1S Horizon Marine Gas Engine Good condition and ready to instal, A premium, large-displacement V8 marine gas engine designed for pleasure boats, sport fishing boats, and large motor yachts. It delivers 370 horsepower at a maximum speed of 4,600 rpm, utilizing substantial low-end torque to efficiently power heavy hulls.

• Displacement: 8.1 Liters / 496 cubic inches
• Horsepower: 370 hp (276 kW) at the crankshaft
• Engine Type: V8 Big Block (GM base longblock)
• Bore & Stroke: 108 mm x 111 mm (Undersquare design built for low-end torque)
• Compression Ratio: 9.1:1
• Fuel Requirement: 87 Octane minimum (Premium 95 RON recommended internationally)
• Weight: 1,130 lbs / 513 kg

• Wide Open Throttle (WOT) Range: 4200 – 4600 RPM
• Idle Speed: 650 RPM (in neutral)
• Aspiration: Sequential Multi-Port Electronic Fuel Injection (MPI)
• Ignition: Distributorless, high-energy ignition system managed by the PCM 555 controller
• Alternator Output: 65 Amp / 917 Watt 

• Horizon Series Closed Cooling: Includes a standard full closed-loop freshwater heat exchanger. This keeps corrosive salt/raw water out of the engine block, massively extending the engine lifespan. 
• PCM 555 Microprocessor: Optimizes the fuel-to-air mixture, knock control, and ignition timing independently for every individual cylinder.
• Engine Guardian System: Constantly monitors over 64 internal functions. It automatically reduces engine power to prevent damage if it senses overheating, low oil pressure, or over-speeding. 
• SmartCraft Digital Technology: Allows seamless connection to digital helm displays, monitoring telemetry, and optional Digital Throttle & Shift (DTS) for smooth mechanical operation. 
• Serviceability Anchors: Features a high-mounted, remote oil filter near the rocker cover to allow messy-free oil changes, and integrated easy-water-drain systems for winterization