Here’s another awesome article reviewing the new 520 Stern Drive by Mercury Racing!
The boys in black have come up with a new stern drive, the 520, as we first reported here. The fuel-injected engine provides recreational performance boaters a new power option. It’s built on the same CNC-machined block that MerCruiser uses for its 430-hp 8.2L MAG HO. It features digital throttle and shift and it’s backed by a two-year limited factory warranty.
Mercury Racing enhances the 520s power and torque by increasing the cylinder bore size with an additional 21 cubic inches of displacement to 523 cubic inches (8.6 liters). The larger displacement, combined with Mercury Racing cylinder heads, multiport fuel injection and an electronic throttle body, provides an extra 100 hp over the 430-hp MAG HO. The great thing is that the engine runs on 87-octane fuel. Addtionally, the 520 complies with EPA and CARB exhaust gas emissions limits.
The key to long life is quality components and the new 520 is designed with a balanced crankshaft, forged I-beam and shot-peened connecting rods and forged aluminum pistons. The aluminum cylinder heads feature optimized valve angles for improved airflow. The valvetrain includes a hardened camshaft for enhanced durability. Performance cam profiles and larger valves compress more air through the engine for greater power and torque, which is essential when you’re working the throttles in an offshore boat during a rough-water run. Mid-range punch should be strong and consistent.
For consistent engine management, the 520 has the same Performance Control Module PCM as on the Mercury Racing 565 and the engine manufacturer’s QC4v family. It offers digital throttle and shift control and it optimizes fuel and spark timing. The PCM also drives Mercury Racing’s Engine Guardian System that detects and alerts an operator of a problem, but also processes the data and reduces power to a safe level that allows the owner to get home. It protects against over heating and low oil pressure. By sensing engine coolant and exhaust temperatures, the system can take action to ensure the health of the powerplant. The system also features one-touch Smart Start and automatic throttle synchronization.
For longer life in saltwater, the 520 comes with closed cooling. The engine also comes with a 65-amp charging system so you can run a wide array of marine electronics. Engine trim is available in 11 color options and the engine comes with Mercury’s Zero Effort Digital controls for optimum command over the motor. It’s available with Bravo One XR and XR Sport Master drives in standard and short lengths.
Source: www.boatingmag.com; Eric Colby, September 24, 2013.