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Overview of Twin Disc MG-509 1.45:1

The Twin Disc MG-509 is a standard marine transmission known for its reliability and versatility in both pleasure craft and commercial marine applications. The 1.45:1 gear ratio is part of the MG-509 SC (Single Clutch) configuration, which is designed for engines with moderate power outputs and is optimized for smoother, faster operation at higher speeds. This ratio reduces the engine RPM to propeller RPM less aggressively than higher ratios, making it ideal for boats prioritizing speed over heavy towing or pushing.

Key Specifications:

Gear Ratio: 1.45:1 (a lower reduction ratio, providing less torque but higher propeller speed for better top-end performance).

Available Ratios for MG-509 SC: The MG-509 SC also offers ratios like 2.00:1 and 2.95:1, but the 1.45:1 is the lowest, suitable for speed-focused applications.

Oil Capacity: Approximately 2.2 U.S. gallons (8.3 liters) for the MG-509 SC, plus additional capacity for hoses and heat exchanger.

Oil Pump Capacity: 8.0 GPM at 1800 RPM and 10.6 GPM at 2400 RPM, ensuring adequate lubrication and cooling under load.

Maximum Speed Limit: Up to 3000 RPM for most configurations, though this can drop to 2350 RPM if equipped with certain drive rings (e.g., A6911).

Housing: Typically includes an SAE Bell Housing #1, which is standard for compatibility with many marine engines.

Weight: Around 300-350 lbs, depending on configuration and accessories (exact weight may vary).