By Eric Colby | Originally published June 15th, 2023
The high-performance division of Mercury Marine marked its 50th anniversary with the introduction of the supercharged V-8 outboard.
Mercury Racing marked its 50th anniversary June 14 by unveiling a V-8 500R outboard during a black-tie gala in Charleston, S.C.
“This is the most exciting production outboard to emerge from Mercury Racing,” general manager Stuart Halley told attendees. “My passion for technology and performance motorsports goes on forever.”
Mercury Racing said in a statement that the 500R delivers more than 500 eager horsepower, 50 more horses and 10% higher torque than the 450R. The 4.6-liter 64-degree powerhead is boosted by a supercharger, and the engine runs on 89-octane gasoline.
Photo: Mercury Racing
The 500R has a 5.9-inch-diameter gearcase that’s available in 20-, 25-, 30- and 35-inch shaft lengths and two drive configurations. The R-Drive is for boats that run up to 85 mph, and the R-Drive Sport is for boats that exceed triple digits. The engine can run with propellers up to 17 inches in diameter.
The lower unit has a 1.60-to-1 gear ratio, and a new water pump increases cooling capacity by 57%.
Upgrades from the 450R include a new crankshaft and larger, more robust 1-inch drive shaft splines. Connecting rods, rod bearings and pistons have been strengthened to handle increased combustion pressure and a 6,600 rpm maximum rpm.
Supercharger boost pressure is increased by 26%, and the 500R has a new attenuator with a larger air intake. Throttle body diameter intake increased from 80mm to 92mm.
Photo: Eric Colby
Mercury said the 500R is the first outboard with a sensor to measure humidity in the air intake to determine the ideal spark timing for the conditions. The company said this can provide up to an additional 30 hp and improved acceleration.
A new Advanced Racing Core midsection has a stronger transom plate that can accommodate 3 inches of vertical adjustment, with seven mounting holes. An enhanced trim system features two main hydraulic rams, plus booster rams. Heavy-duty guide plates and stiffened engine mounts provide stability.
The 500R is available in Phantom Black or Cold Fusion White.