Mercury Racing 500R outboard engine revealed

The new flagship engine features a Mercury Racing supercharger to produce an extra 50 ponies and a 10 per cent increase in torque over the 450R it now supplants at the top of the performance tree.

However, it’s not just a supercharger and a prayer. Mercury Racing has made major changes to the block used for the 450R so it now features a hardened powerhead design, a more efficient cooling system, an all-new midsection and steering system, and a larger 5.9-inch torpedo on the gearcase.

The result is an outboard engine that Mercury claims “offers incredible mid-range punch and pulls with unrelenting authority all the way to wide-open throttle”.

It’s not just for racing, either. Mercury Racing anticipates that most of these outboard engines will be snapped up by owners of a new breed of the “fastest luxury sport boats” on the market.

To this end, the Mercury Racing 500R was developed with two lower legs; a base R-Drive for boats capable of speeds of between 74 and 87 knots (85 and 100mph) and a more advanced R-Drive Sport for performance catamarans and centre consoles capable of reaching beyond the imperial ton in speed over the water.

At higher speeds, the engines become like surface drives, with the R-Drive Sport featuring a longer skeg to maintain steering at warp speed, and a water pick-up designed for full surface running. Both versions of the drive feature a 1.60:1 gearing, thicker drive and prop shafts, and can take up to a 17.0-inch propeller – an inch larger than the 450R.

Best of all, those performance figures are generated on standard unleaded fuel, not the premium stuff.

According to Mercury Racing, the upgraded crankshaft rides in 230-degree groove main bearings “for improved oiling”, and features larger, more robust one-inch driveshaft splines. 

“Connecting rods, rod bearings and pistons are strengthened to handle increased combustion pressure and a higher 6600 RPM redline,” it says. “A new low-inertia flywheel allows the engine RPM to climb faster for improved acceleration.”

The supercharger used on the 500R increases its boost pressure by 26 per cent compared with the 450R, with a new attenuator featuring a larger intake helping the engine breathe. The throttle body diameter rises from 80mm to 92 mm, and the supercharger’s intake features a new design that helps it stuff more air in.

Something that Mercury claims is new for a marine engine is a new humidity sensor mounted in a redesigned intake attenuator that measures air moisture and changes the engine’s spark timing, yielding up to 30hp more when, say, following the spray kicked up by a boat in front.

In testing, the new technology helped to cut a massive 17 seconds off a test boat’s 0-70mph sprint, Mercury claims.

A redesign of the 500R’s midsection features a new seven-hole transom plate with much more vertical adjustment than the six-hole version on the 450R, as well as a couple of booster rams added to the main rams to help with trim under full load.

A beefed-up steering system applies up to 18 per cent more torque, with the tubes swapping out from aluminium to stainless steel to handle the extra load. 

The Mercury Racing 500R will be available in 20-, 25-, 30- and 35-inch lengths to work with single or multi-engine performance applications, while the new mid-section features a 26-inch mounting distance, making multi-engine installations or repowers easy.

Like your colours? The Mercury Racing 500R will be available in black or white with Mercury Racing graphics and “Red Devil” trim panels. You can also order it in stock black to paint it any colour you want.

In the US the 500R will be covered by a three-year limited factory warranty with up to five years of extended factory warranty available. 

No mention was made of pricing.