MerCruiser Inboards   
Big-Block V-8 - 8.1S HO    

Gas - Carbureted

• 5.7L

Gas - Fuel Injected

• 350 MAG MPI
• 350 MAG MPI Horizon
  
  
• MX 6.2 MPI
• MX 6.2 MPI Horizon
  
  
• 8.1S Horizon
• 8.1S HO

Diesel

• D2.8L D-Tronic
• D4.2L-LD
• D4.2L
• D4.2L D-Tronic
• 7.3L D-Tronic-LD
• 7.3L D-Tronic

• Propshaft Horsepower: 420 (315 kW)
• Displacement (Liter/CID): 8.1/496
• Cylinders: V-8
• Bore & Stroke (in/mm): 4.25 x 4.38/108 x 111
• Compression Ratio: 9.1:1
• Fuel System: MPI
• Full Throttle RPM Range: 4400-4800
• Ignition Type: PCM 555 distributorless
• Alternator: 70
• Length (in/cm): 35/89
• Width (in/cm): 33/84
• Height (in/cm): 24/61
• Weight (lbs/kg): 1130/513

Transmission Ratios

• Gear Ratio - Velvet Drive 71C: N/A
• Gear Ratio - Velvet Drive 72C: N/A
• Gear Ratio - Velvet Drive 5000A: 1.5, 2.0, 2.5, 2.8:1
• Gear Ratio - Velvet Drive 5000V: 1.5, 2.0, 2.5:1
• Gear Ratio - Hurth 630A 1.5/2.0/2.5/2.7:1
• Gear Ratio - Hurth 630V 1.5/2.0/2.5:1

Standard Features

• Engine Guardian system
• Closed-cooling with long-life coolant
• Stainless steel exhaust elbows
• Quick-drain oil system and remote oil filter
• Single-point raw water drain system
• Water-cooled fuel system
• Color-coded service points
• Platinum-tipped spark plugs and high temperature spark plug wires

Optional Features

• 2", 5", and 7" exhaust risers (kit)

Boating Benefits

• 3-year extended maintenance interval (except for periodic fluid-level checks and seasonal oil and filter changes).
• The PCM 555 processor, which makes the 8.1S Horizon Smartcraft™ ready for the future of integrated marine propulsion.
• Closed-cooling with 5-year coolant.
• Innovative new single point air actuated raw water drain system, which enables boaters to extend their boating season into the cold months.
• Stainless steel exhaust elbows, aluminum exhaust mainfolds and dry-joint technology that provide the exhaust system with unmatched corrosion resistance.
• Engine Guardian™ that not only detects and alerts boater of an engine problem, it processes the data and reduces power to a maximum, safe level that allows the boater to continue operation.
• Exclusive Mercury MerCruiser® service dealer network.