Mercury Racing 300X Pro Max Tech Specs

Technical Summary: Mercury Racing 300X 3.0L 2-Stroke V6 Outboard

The Mercury Racing 300X Pro Max is a high-performance 3.0-liter, two-stroke V6 outboard designed for competitive and high-speed applications. It features advanced fuel injection, a high RPM range, and a lightweight yet durable build optimized for power and efficiency.

Engine Specifications

• Type: Two-cycle, 60° V6

• Displacement: 185 cu. in. (3044 cc)

• Stroke: 3.00 in. (76.2 mm)

• Cylinder Bore: 3.625 in. (92.075 mm)

• Compression Ratio: 6.2:1

• Peak Power Output: 300 HP (224 kW)

• Full Throttle RPM Range: 6200 - 6800 RPM

• Idle RPM (In Gear): 800 - 850 RPM

• RPM Limiter: 7100 RPM

• Peak RPM During Break-in: 5800 RPM

Fuel & Injection System

• Fuel Injection: ECM-controlled, crank-angle-driven

• Injectors: 6 individual injectors

• Fuel Line Pressure: 39 ± 2 psi (268.9 ± 13.8 kPa)

• Fuel Type: Unleaded gasoline (minimum 92 octane)

• Fuel/Oil Ratio (ECM Controlled):

  • Idle: 250:1

  • WOT: 40:1

• Fuel Pressure:

  • Idle: 2 psi (13.8 kPa)

  • WOT: 8 psi (55.2 kPa)

Ignition & Electrical System

• Ignition Type: Digital Inductive

• Firing Order: 1-2-3-4-5-6

• Spark Plug Type: Champion QL77PP

• Spark Plug Gap: 0.025 in. (0.63 mm)

• Alternator: Delco Remy, 12V, 50A

• Battery Requirements:

  • Minimum Marine Cranking Amps: 1000

  • Minimum Cold Cranking Amps: 800

  • Amp Hours: 105 Ah

Lubrication & Cooling

• Oil Injection Type: Electronic oil injection

• Recommended Oil: Quicksilver/Mercury TC-W3 Premium Plus 2-Cycle

• Engine Oil Tank Capacity: 1.5 US qt (1.42 L)

• Boat Oil Tank Capacity: 3 US gal (11.4 L)

• Cooling System: Thermostat controlled

• Thermostat Opening Temperature: 120°F (49°C)

Gearcase & Propulsion

• Available Gearcases:

  1. Fleet Master (1.75:1 ratio)

  2. Torque Master (1.75:1 or 1.62:1 ratio)

  3. Sport Master (1.75:1 or 1.62:1 ratio)

• Gearcase Capacity: 28.0 fl oz (828 ml)

• Reverse Gear Backlash: 0.030 - 0.060 in. (0.76 - 1.52 mm)

• Water Pressure @ RPM:

  • Idle: 1.5 - 4.5 psi

  • 5000 RPM: 10 - 12 psi

Midsection & Mounting

• Shaft Length:

  • Standard: 20” (508 mm)

  • Long Shaft: 25” (635 mm)

• Full Trim/Tilt Range:

  • Standard: 71°

  • Offshore: 72°

  • Power Trim Tilt: 19°

• Steering Pivot Range: 60°

• Maximum Transom Thickness: 2-3/8 in. (6.03 cm)

Guardian Engine Protection System

The Guardian System limits power in critical conditions:

• Break-in Period: Limits power to 75%

• Low Oil in Engine Tank: Limits power to 95%

• Critical Low Oil: Limits power to 10%

• Loss of Oil Pump Pressure: Limits power to 10%

• Overheating/Low Water Pressure: Limits power between 95% and 10%

• Battery Voltage Issues:

  • <12V: Decreases power to 50% at 11V, 0% at 10V

  • >16V: Reduces power to 50% at 17V, 0% at 18V

The Mercury Racing 300X 3.0L V6 is a powerful, high-RPM, performance-focused outboard designed for racing and high-speed applications. It integrates advanced ECM-controlled fuel injection, a Guardian protection system, and multiple gearcase options for durability and efficiency. The lightweight construction and high RPM range make it an excellent choice for high performance use.

Download the 6-page Mercury Spec Sheet in PDF - Free Online

mercury-racing-300x-pro-max-specification.pdf

Download PDF • 32KB

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