OUTBOARD ENGINE GUIDE: Which is the best new outboard motor for your boat?

OVERVIEW
The impetus for the development of modern four-stroke and direct fuel-injected (DFI) two-stroke outboards engines in recent years has been the increasingly stringent exhaust emissions regulations being implemented around the world, particularly in the US and Europe.

>> 2019 outboard engine guide: Which is the best new motor for your boat?

Until recently, Australia has dragged the chain on emissions standards — at least compared to most other developed countries — but we have now caught up and new emissions standards for non-road spark ignition engines and equipment (NRSIEE) are scheduled to be introduced on July 1, 2018.

The new Yamaha F25 four stroke is the modernday answer to the demise of the traditional two-stroke carby outboard.

Going forward from July 1, 2018, outboard engine manufacturers, importers and distributors will no longer be able to import traditional carby two-stroke outboards, or any other outboard engines that don't meet the new standards.

Remaining stocks of new carby two-stroke outboard engines will still be available for sale from dealers post July 2018, but only for the 12-month period until 1 July, 2019, at which point all retail sales of the older-style two-stroke outboards will be banned.

Ever-tightening emissions regulations is great news for Mother Nature, as modern outboards are far cleaner running and less polluting than their predecessors.

Fortunately for boatowners and fishermen, modern outboard engines are not just environmentally friendly, but much better engines in general.

Four-strokes and the latest DFI two-stroke outboards are also more reliable, quieter, smoother, and much more economical than the smoky, clackety old outboards of yesteryear.

So, without further ado and regulation here's a rundown of what the big outboard engine brands have to offer in 2018 and beyond…

The Japanese manufacturer was unquestionably the first to develop a range of low emissions outboard engines.

HONDA'S LOW EMISSIONS OUTBOARDS
The Japanese manufacturer was unquestionably the first to develop a range of low emissions outboard engines. Honda has been producing four-stroke outboards since the late 1960s, but it wasn't until the early 1990s that Honda set out to become a major force on the world outboard stage.

The release of the Honda 45hp in late 1992 heralded the start of a revolution in outboard technology as this Japanese giant followed the initial four-stroke offering with a succession of models culminating with the launch of its 250hp V6 outboard.

Japan's Honda Marine introduced its first four-stroke outboard in the 1960s, and followed this up in 1992 with the first of the modern four-strokes, the BF45. Pictured is one of the newest models, the portable BF4, which we reviewed in late 2016.

Honda now has a full range of four-stroke outboards with 20 models to choose from between 2.3 and 250hp. You can read about Honda's latest 2018 releases in this news article titled Honda refreshes its V6 outboard line-up for 2018. 

YAMAHA OUTBOARD RELEASES
Japan's largest volume outboard manufacturer has also developed an extensive range of four-stroke outboards. These sophisticated engines were introduced to complement Yamaha's renowned traditional two-stroke outboard range - but the new, reduced-emissions four-stroke models are now far more popular.

The Yamaha four-stroke range commences with a 2.5hp portable outboard and tops out with a massively powerful 350hp V8, although there is rumoured to be a 400-450hp monster V8 in the pipeline.

In between you'll find more than 30 different models, including the popular F60 and F70 lightweight mid-range models and the newly-released F25 and F90, plus the VMAX SHO 90 and more.

Yamaha launched the F90 last year to fill a gap in the Yamaha four-stroke mid-range. This light weight 1.8L in-line four-cylinder outboard is ideal for powering trailerboats in the 4.2m-5.2m size range.

SUZUKI GOES BIG
Another Japanese brand that has grown substantially during the last decade. Since being re-introduced to Australia in 2003 by the Haines Group, Suzuki Outboards have enjoyed considerable success - thanks to a superb range of four-stroke outboard engines stretching from 2.5hp and running through to the brand new DF350A we featured recently.

Suzuki's all new DF350 4.4L V6 four stroke outboards are the first on the market to be equipped with contra-rotating propellers for improved directional stability and better low speed manoeuvrability in single engine installations.

Check out this article title the 5 things we love about the biggest ever 350hp Suzuki outboard following our test.

The most recent addition to the Suzuki range is the DF325A, which has been designed specifically to be able to run on lower, 91 octane fuels, thus providing customers with worthwhile savings at the fuel pump.

EVINRUDE'S E-TEC OFFERINGS
Evinrude E-TEC: Bombardier Recreational Products (or BRP) is the manufacture of the Evinrude E-TEC range of direct fuel injected two-stroke outboards.

The Evinrude E-TEC range of direct fuel injected two-stroke outboards starts at 25hp and runs through to a 300hp V6. Pictured is the compact, low profile 30hp tiller model with electric start and power trim and tilt.

Distributed in Australia by Quintrex parent company, Telwater, Evinrude E-TECs are available in a wide range of sizes from 25hp through to 300hp — and with specialist high power and multi-fuel models.

At the top of the Evinrude E-TEC range is the recent G2 series, available in 150, 175, 200, 225, 250, and 300hp models. You can read about the Evinrude E-TEC G2 150hp, 175hp, 200hp: Australian launch, and the global launch we attended of the original G2 300hp in the U.S. 

These futuristic looking outboards are equipped with a host of performance and technology improvements over their predecessors and are available in a range of custom colours so you can colour-match your G2 E-TEC to your boat.

The E-TECs are complemented by a range of four-stroke portable engines from 3.5hp-15hp.

The new V6 Mercury outboards are making a bold statement about style and function.

MERCURY MARINE STEPS UP
Mercury Marine has tackled the low emissions outboard issue by embracing both four-stroke and DFI two-stroke technology.

Mercury's carburetor and EFI four-stroke outboards start at 2.5hp and now extend up to 225hp. This range did top out with Mercury's best selling 150hp EFI model, but recently we have seen the release of three exciting new super light weight 3.4L V6 four-strokes in 175, 200 and 225hp. We can't wait to get hold of one of these striking looking new engines for a full test and review.

You can read about the new V6 Mercury outboards in this article titled New 2018 Mercury V6 175hp, 200hp and 225hp FourStrokes dare to be different. 

In addition to what is now a full range of naturally aspirated four-stroke outboards, Mercury also has a high-powered range of super-charged four-stroke outboards called Verados - starting at 135hp and extending through to the Mercury Racing derived 400R.

Mercury also just released a new high-performance 150hp Mercury Pro XS FourStroke Outboard, a we reported on here.

On the DFI two-stroke front, Mercury's long running Optimax range continues to be popular with boaters and fishermen, but has been refined in recent years. Standard Optimax models are available in 200, 225, and 250hp classes, while the high performance orientated ProXS Optimax models are available between 150hp and 250hp.

Tohatsu is another manufacturer with both four-stroke and DFI two-stroke outboards. Pictured is the battery-less EFI 15hp model which weighs just 43kg in the short shaft configuration.

Four-stroke Tohatsu engines are available from 2.5hp to 250hp — though the models above 75hp are made for Tohatsu by Honda.

Like Mercury Marine and Evinrude, Tohatsu has a series of DFI two-stroke outboards. Tohatsu's TLDI (two-stroke low pressure direct injection) models are available in 40, 50, 90 and 115hp classes.

Tohatsu's 50hp EFI three cylinder four-stroke weighs just 97kg and is available with variable trolling/idle speed control and a tiller-arm for open boat applications.

The exception and the most respected of the Chinese brands is Parsun. Though best known to date for its carby two-strokes, Parsun also has a range of low emissions four-stroke models from 2.5-25hp, but with more powerful models on the horizon.

The 300hp OXE diesel is destined for commercial use and military application where petrol isn't carried aboard.

LPG, DIESEL AND ELECTRIC
There are also expanding ranges of LPG outboard engines from the likes of Tohatsu and LEHR, as well as diesel outboard from OXE like this 300hp offering launched locally, and this Neander 50hp Dtorque 111 turbo-diesel outboard now available on the local scene through Power Equipment.

Torqeedo has launched in Australia with an increasingly powerful range of marine electric engines also available through the Yanmar distributor Power Equipment. You can read more about the initial range release in this article Torqeedo electric motors launch in Australia.

Yamaha's flagship outboard engine is the superb 5.3L V8 350hp. Here's a pair of them onboard a big Grady-White sports boat.

FOUR-STROKE VS DFI TWO-STROKE
Meantime, debate rages over the respective merits of four-stroke and DFI two-stroke outboards.

Exponents of four-stroke technology maintain that four-stroke outboards are inherently more reliable and more durable than two-strokes, regardless of whether you are talking about traditional two-strokes or modern, DFI models.

Feedback from commercial fishermen, rescue groups, etc, (who run up thousands of engine running hours each year) would seem to confirm this position, but then two-stroke advocates will vehemently disagree.

In recreational boating applications, one could argue the overall durability and longevity of an outboard is more likely to be influenced by the way the engine is treated and maintained than if it is a two-stroke or a four-stroke.

Recreational boaters usually clock up less than 100-150 hours per year and, on that basis, and with regularly servicing and maintenance, you can expect a decade or more of reliable engine performance regardless of whether your engine is a two-stroke or a four-stroke.

Treat it badly, miss your scheduled services, forget to clean and flush the engine regularly, and you can expect the operating life of your engine to be significantly reduced — regardless of engine type.

In the debate between two-stroke and four-stroke outboards, reliability is just one issue; there are several others to consider, like acceleration…

There is no questioning the raw power and punch of the direct-injection two-stroke outboards from Evinrude ETEC.

TWO-STROKE PUNCH
If you are looking for the torquey, punchy performance you might be used to with older-style two-strokes, then you might be disappointed with the performance of some four-stroke outboards.

With the exception of the latest electronic fuel injected or super-charged models, four-strokes do not have the sheer out-of-the-hole punch of a DFI two-stroke.

Mercury Marine has four-stroke and DFI two-stroke low emissions outboards available. The long running Optimax DFI two-stroke range has been refined in recent years with models now available only between 150-250hp.

Like the older two-strokes, DFI outboards provide a big kick down low in the rpm range, and respond with more urgency when you stab the throttle, which is ideal for water skiing and other high-performance orientated applications.

DFI two-stroke outboards, as a rule, are still lighter in weight than comparable four-strokes too — although the gap between them is closing rapidly.

Evinrude's G2 series of direct fuel injected E-TEC two-stroke outboards are available between 150-300hp. These compact, futuristic looking low-emissions motors provide class leading hole-shot and mid range performance coupled with economy.

TWO-STROKE OR FOUR-STROKE FOR FISHING?
For fishing applications, choosing between a DFI two-stroke and a four-stroke outboard is a difficult task.

If your style of fishing involves many long hours of low speed trolling and mid-range cruising then a four-stroke engine could serve you best. This is because four-stroke engines have a much more progressive power and torque curve.

With the DFI two-strokes, the power tends to come on with a rush, but with four-strokes, the delivery of power is more even through the entire rpm range. In an offshore cruising situation, this smoother delivery of power enables smaller, finer adjustments to speed and rpm when traveling in adverse conditions.

Conversely, however, the instant power from a DFI two-stroke will certainly come in handy in rough weather when you need immediate throttle response to run between waves and/or power up the back of a wave when coming in through a bar, etc.

Big outboard power is all the rage at present. The Boston Whaler 420 Outrage we tested last year was rigged with quad Mercury 350hp Verado super-charged four-stroke outboards... for a combined total of 1400hp!

BUT WHAT ABOUT FUEL ECONOMY?
In other areas, four-stroke and DFI engines tend to be pretty even. Overall fuel economy and emissions are pretty similar, while with regard to noise and vibration, most experts would agree that four-strokes are marginally smoother and quieter, but this is still subject to some debate!

Similarly, advocates of DFI engines will argue that DFI outboard-powered boats will achieve a slightly higher top speed than an identical boat with four-stroke outboard power.

Two-stroke exponents will also point out that four-strokes are also more expensive to maintain.

Four-strokes don't require a constant oil supply like a DFI two-stroke, but they do require regular oil and filter changes and have more moving parts to service and adjust. For this very reason, service intervals tend to be closer together and costlier with a four-stroke. Then again, the oil for two-stroke engines isn't cheap.

THE VERDICT
What is readily apparent from extensive testing of both four-stroke and DFI outboards is that these low emissions engines are vastly superior to the "traditional" two-stroke outboard in most areas.

Four-stroke and DFI outboards are much more economical, smoother, cleaner, quieter… and generally much easier to live with.

In light of this, we suspect few people will lament the loss of traditional two-stroke outboards when they are ultimately banned from retail sale.

But for those on a tight budget, the old two-strokes will be around for a while longer, including upon the thousands upon thousands of second-hand rigs listed for sale on our sites. Resale value of second-hand carby two strokes may drop, however, so expect some bargains if you want to power a second-hand tinny and create a cheap but reliable fishing rig. - Jeff Webster words and pics.

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