All the 150hp outboard engines compared

Given the high volume and huge market for 150hp outboard engines, it should come as no surprise to find that all of the big brands have at least one 150hp model in their respective model ranges.

Outboard engines these days are all very safe, reliable, durable and user-friendly. Huge advances in technology made in recent years are reflected in the improvements in power-to-weight ratios for these engines pretty much across the board and in the increased torque and low-down power delivery of the four-stroke outboard engines in particular.

Buyers also have ample choice of 150hp outboard engine models. Let's now examine the individual offerings from each of the five top engine makers.

The Honda BF150 is the oldest engine in this group, but highly regarded for its smooth, reliable, clock-like performance.

Launched alongside its 135hp sibling way back in 2004, the BF150 is a 2.4-litre in-line four-cylinder, twin overhead cam four-stroke outboard equipped with Honda's renowned VTEC (variable valve timing and electronic lift control) to maximise power and fuel economy at low and high rpm.

The BF150 was sourced originally from Honda's automotive division, using an engine best known for powering Honda's Accord family cars. As a result, the reliability and longevity of the Honda BF150's 16-valve, twin-cam four-cylinder engine were never in question.

More than a decade after their debut, both the BF135 and BF150 continue to score very highly in customer satisfaction surveys worldwide.

Despite being one of the oldest 150hp outboard engine designs on the market, the Honda BF150 remains competitive with its rivals.

Key features such as VTEC, lean burn control technology, multi-port programmed fuel injection, boosted low-speed torque (BLAST), a three-way cooling system (to keep the cylinder heads cool) and a dual-stage induction system (for better breathing) combine to deliver excellent performance and economy.

Extra features include a 2.14:1 gear ratio, a belt-driven 40-amp alternator for running onboard electrics, NMEA 2000 compatibility, freshwater flushing port, variable idle revs for low-speed trolling, and engine alerts for pretty much every possible fault.

In 2021, the BF150 was updated to offer the choice of a conventional cable rigging system or Honda’s iST (intelligent shift and throttle) digital fly-by-wire control. For multiple engine installs, the digital system allows the skipper to control all the engines using a single throttle control and trim switch.

 It also gained a push-button start as well as a traditional key start, and new gauges to give the helm more information about how the engineers are performing.

With regard to engine weight, the BF150 is on par with its four-stroke outboard competition, weighing 217kg for the lightest model.

That's pretty impressive and confirms that this ultra-reliable engine can still mix it with the latest releases from rival brands.

Honda does not have its own joystick control system for the BF150. Instead, the engines are compatible with Seastar’s Optimus 360 joystick steering, Seaways by Dometic virtual positioning and SeaStation by Dometic virtual anchoring.

The Honda BF150 (and the identical Tohatsu 150hp) is available in longshaft (20-inch), extra-longshaft (25-inch) and counter-rotating configurations and comes with a five-year factory warranty for recreational use.

If you have an authorised Honda Marine dealer service your outboard engine by the book for the entire five-year warranty period, Honda will throw in an extra two years of warranty coverage. 

A three-year warranty covers commercial applications.

Mercury's 150hp 3.0-litre in-line four-cylinder four-stroke outboard engine has been a huge success for Brunswick's Mercury Marine, and for good reason.

The Mercury boasts the largest displacement 150hp four-stroke outboard engine, but the lightest weight (206kg) in this group. This combination helps to provide smooth, effortless power to all manner of boats.

The compact-sized, lightweight Mercury is particularly well suited to weight-sensitive hulls in the 5.2-metre to 6.0-metre metre range.

The 3.0-litre Mercury 150hp was launched in 2011. Designers opted for a big displacement, naturally aspirated engine configuration hoping to achieve comparable power and torque figures to outgoing two-stroke models.

They did a fine job of it, too. On the water, the 150hp Mercury has proven to have significant low-down power and torque for excellent hole shots and impressive mid-range pick-up.

We’d rank Mercury’s 150hp as the best engine for low-down power and throttle response.

If the standard Mercury 150hp is a powerhouse performer, then the uprated ProXS model is a step up again. Rumoured to deliver around 160hp at the propeller, the 150 ProXS is the four-stroke outboard engine of choice for high-performance applications and tow sports.

In design specifics, the 150hp Mercury is an in-line four-cylinder engine with a single overhead camshaft arrangement with eight valves. 

Mercury claims this simpler engine configuration reduces servicing and maintenance costs when compared with 16-valve twin-cam engines that require valve clearance adjustments.

The 150hp Mercury can rig with mechanical and hydraulic steering, and with digital or analogue engine gauges, making it ideal for repower applications. Mercury doesn’t offer a joystick control system on single-engine applications, and is yet to expand the system to include its four-cylinder outboard engine range.

Servicing intervals are 12 months or 100 hours apart (after the first service) and the factory warranty period is six years for all recreational outboard engines.

Launched in 2016 and updated again in 2018, the mechanical control Suzuki DF150A and digital control DF150AP have the second-largest capacity in the 150hp outboard engine class with a displacement of 2867cc (just shy of Mercury's 2998cc). 

The big Suzuki is the heaviest of the 150hp outboard engines on offer, tipping the scales at 235kg for the lightest mechanical control model and 241kg for the digitally controlled version.

That said, the big displacement and solid power delivery from this engine compensate to a degree for its added bulk. 

The Suzuki also carries a 2.5:1 gear ratio to allow the engine to swing big propellers for powering large offshore fishing craft in single- and dual-engine applications.

In design specifics, the Suzuki DF150A/AP is an in-line four-cylinder, twin cam 16-valve four-stroke engine with a square bore of 97mm x 97mm.

The DF150A and AP share their engine architecture with the physically identical DF175A and the award-winning DF200AP.

Key features of the DF150A/AP include an offset driveshaft for better balance and reduced vibration; a unique two-stage gear reduction system; self-adjusting, maintenance-free timing chain; multipoint sequential EFI; and Suzuki’s “Lean Burn” control system for improved economy and engine efficiency.

Other innovations include a knock sensor to allow the engine’s computer to adjust ignition timing for optimum efficiency, along with an O2 sensor to monitor fuel/air mixtures and a water detection sensor to pick up on moisture in the fuel system and react accordingly to protect the engine.

Similar to most modern four-strokes, the DF150A/AP is equipped with many user-friendly features including malfunction warning systems; instant starting; cowl-mounted trim switch; tilt-limit switch; dual flushing ports; start-in-gear protection; 12-volt, 44 amp alternator (not as big as some, but it kicks in at just 1000rpm); NMEA 2000 compatibility; speed and fuel flow instrumentation; and more.

The Suzuki DF150A is available in 508mm and 635mm shaft lengths while the Suzuki DF150AP comes in only a 635mm shaft length. There is also a choice of colours; traditional black along with the more expensive cool white.

Suzuki is the only outboard engine manufacturer to give you a hint at how much a new powerplant is going to cost you. At the time of writing, the DF150A was priced from $22,120 with forward controls and gauges adding an extra $2200. This price is also before the added costs of fitting.

The Yamaha F150 is the world's best-selling 150hp four-stroke outboard engine, and it continues to dominate the sales charts. 

The original F150 made its debut in 2003, but new iterations of this iconic engine have followed and there are now a couple of slightly different models to choose from.

In appearance, the latest F150 outboards are identical to the larger F175 and award-winning F200.

However, the standard F150 has a slightly smaller engine capacity at 2670cc, as well as a different gear ratio, a lower output alternator (36 amp vs 50 amp) and mechanical controls.

This standard, older configuration Yamaha F150 is expressly designed, and ideal, for engine repower applications that use existing analogue engine instruments and mechanical cable rigging.

If you are buying a brand new boat and want the full digital experience, the uprated F150 DEC (Digital Electronic Control) or the slightly more powerful VF150 VMAX SHO (Super High Output) are the best options.

Both have an enlarged 2785cc displacement and 50 amp alternators, while the F150DEC model has a gear ratio of 1.86:1 to match the larger F175 and F200 outboards, as well as integrated electric steering.

Similar to the Suzuki and Honda 150hp engines, the Yamaha F150 has an in-line four-cylinder twin-cam 16-valve engine. The engine is slim in design and the compact powerhead shape and 600mm mounting centres make this engine ideal for twin-engine installations.

The two larger capacity Yamaha 150hp outboard engines also have an electronic throttle valve working in harmony with the electronic fuel injection and ignition systems to achieve excellent performance and fuel economy.

Similar to the F200, the 150hp VMAX also has variable camshaft timing for boosted low- and mid-range torque.

As you would expect from Yamaha, these engines are brimming with features including an offset crankshaft for more efficient transfer of power; Yamaha's Shift Dampener System for smoother, quieter gearshifts; variable trolling control to change the idle speed in 50rpm increments; compatibility with the NMEA2000 protocol for running third party displays; and with Yamaha's Command Link Plus digital instrumentation.

The digital-friendly versions of Yamaha’s F150 are also compatible with its Helm Master EX joystick control system.

It’s not due on sale in Australia until late in 2023, but the new Rotax S engine – we’re not sure yet whether it is officially classed as an outboard or sterndrive – rates a special mention.

The Rotax S is the child of the stillborn plan from Evinrude to take the outboard engine world by storm by building a lightweight but powerful family of G2 outboard engines rated from 115hp to 150hp.

The engines featured a 1.7-litre three-cylinder engine with direct injection and a set-and-forget two-stroke oil system.

The engine has resurfaced several years lantern, but this time as a semi-submerged, 180-degree drive system that steers like an outboard engine, but sits below the waterline like an inboard engine. The main benefit of this is it creates a flat transom that opens up a lot of real estate down the back of the boat.

But you’re not going to buy an engine, as you need a special boat to wrap around it. In Australia, it’s the Quintrex Freestyler X.

We’re yet to spend time with the new Rotax S, which will be sold here as either a 115hp or 150hp version, so we can’t really say how well they perform.

One of the big benefits of the outboard engine on which this powerplant was based was that it did not need servicing in the first five years of use, only an inspection to ensure it was performing optimally. We’re not sure yet if this service schedule will carry across to the new Rpotax S version.

Specifications
Model: Rotax S150
Pricing: N/A
Engine type: Two-stroke direct injection
Cylinders: In-line 3-cyl
Fuel management: EFI
Weight: 255kg (lightest model)
Displacement: 1865cc
Bore x stroke: N/A
Maximum output: 150hp @ 5500rpm
Operating range: 5000-6000rpm
Shaft length: 635mm (25-inch)
Alternator: 12V/40A
Trim method: Power trim/tilt
Gear ratio: N/A
Recommended fuel: Regular unleaded
Gearcase oil capacity: 1.5L
Counter-rotating: Not available
Servicing: 5 years (inspection recommended every 100 hours)
Emissions rating: CARB 3-star/OEDA 3-star
Warranty: 5 years (when serviced at Quintrex dealer)