Mercury Racing 360 APX Outboard

New Apex Series Four-Stroke V8 designed for Formula 1 Tunnel Boat competition.

September 18, 2020
Mercury Racing APX Motor Article
A specialized gearcase and midsection help make this a racing competition outboard. Courtesy Mercury Racing

Mercury Marine’s 4.6 liter V8 outboard platform is like a tree with many branches. From the root V8 Four Stroke engine, many varieties of outboard spring to cover the many niches of marine propulsion: from luxury-performance Verado, to the commercial Sea Pro lineup, to the Pro XS tournament bass engine.

And of course, Mercury Racing, the branch from which the new APEX 360 outboard comes from.

Mercury Racing, a separate division of Mercury Marine, builds the R series of outboards for performance-oriented consumers, plus performance sterndrives, as well as manufacturing refined propellers, developing special lubricants and creating a host of parts and accessories that serve performance boaters. It is about the only player in the high-performance propulsion and parts and accessories space. The new APEX 360, stylized as APX on the cowl, confirms that. Just as there is no other marine engine maker like Mercury Racing there is no other outboard like this one on the market.


“This is a, ‘racing competition,’ engine,” asserts, Stuart Halley, Mercury Racing General Manager. That is to distinguish Apex series outboards from Mercury Racing’s high-performance consumer offerings. So, what’s the diff?

The 360 APX is specifically intended to power Formula One tunnel boats on the UIM F1 H2O World Championship. It is only available to qualified race teams. Warranty? There is none. It also boasts a 12-inch midsection, ideal for tunnel boats, but not so much for a center console or runabout. It is rated at 360 propshaft horsepower, redlines at 7000 rpm and the 12-inch midsection features integral trim and lift.

Full specs and model details for Mercury Racing 360 APX Outboard »


The 360 APX is normally aspirated, retains its double overhead cam/four-valve architecture and the compression ratio is increased from 10:1 to 11:1. The powerhead is fitted with a short-runner intake manifold mated to a cold-air induction system vented through the cowl. The engine calibration is modified to take full advantage of the powerhead modifications. The 360 APX uses a 24-volt starter for faster dock-side starting in competition. The above water exhaust provides unrestricted flow, but also ensures race fans hear race noise. Additionally, it produces 90% lower emissions than current two-stroke racing engines. It is notable that Union Internationale Motonautique (UIM) President, Dr. Raffaele Chiulli, believes this engine shows the race organizations commitment to lowered emissions. Halley posits that between the engines efficiency, and its ability to burn premium pump gas instead of race fuel, it will markedly lower race teams fuel bills.


The 12-inch midsection is all-new and designed specifically for Formula 1 tunnel boat applications, with a structural wet sump driveshaft housing and integrated power trim and power lift with remote pumps. An overdrive spur gearset between the crankshaft and the gearcase increases the input shaft speed to the gearcase to match that of the current 9600-RPM two-stroke race engine, and produces the left-hand propeller rotation desired for Formula 1 circuit racing. The overdrive gears accommodate multiple gear ratios, so teams can select the ratio that best fits each particular race.

Mercury Racing APX 360 - special feature is the above water exhaust that ensures race fans get the sound of a racing outboard.
Another special feature is the above water exhaust that ensures race fans get the sound of a racing outboard. Courtesy Mercury Racing

Halley let on that Apex is a reference to a where a driver in circuit racing is usually looking—to the apex of the turn. That it serves as a double-entendre in branding the 360 APX as at the pinnacle of mission-specific design makes it an apt moniker for this new racing competition outboard. First in a series, it slated to be available late fall of 2020.


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