Honda four-thought

Mark Meyer | VOLUME 23, ISSUE 6

With today’s volatile fuel prices, Honda’s four-stroke outboards make sense…

There’s no doubt about it, boating has become quieter and more fuel efficient over the past few years. Not to mention more ecologically friendly. A visit to your local ramp on a weekend will show you what I mean. Less smelly old technology two-strokes and more four-strokes and new technology two-strokes is the trend.

Most of the big players in the outboard engine market have been making the transition to offer a greater range of four-strokes and, in one case, a new technology two-stroke. While two-strokes will remain readily available, the manufacturers of those engines will readily admit there’s a lean towards the latest technology available.

When it comes to four-stroke power, Honda doesn’t know any different. It has been building four-stroke engines since 1948 and recent innovations have put some punch into four-stroke performance across its range.

We took a look at Honda’s trailer boat engine range while on the Gold Coast recently, including a Mako 650 Island Cab fitted with a 150 VTEC outboard. These boats are an evolution of Alf Stessyl’s Yellowfin boats that were around in the 1980s. These earlier boats featured a constant deadrise along the entire hull, and in the Mako it has been modified to a beam 220mm wider, along with reversed chines. With a 5mm bottom and 4mm sides and deck, it weighs in at 2.6 tons on a trailer and so is a substantial hull to push along.

Honda’s VTEC labelling stands for ‘Variable valve Timing and lift Electronic Control’, which was introduced to Honda’s high performance sports cars in the 1990s and is now a feature in all of its production line and Formula One racing cars. Honda claims it offers smooth, stable idling, with reduced fuel consumption and greatly increased power through the top end of the rev range.

There’s no argument from us on any of these claims. While we couldn’t check the fuel consumption at idle, you could sit a full glass of water on the engine cowl without it spilling and it would be hard to imagine Honda getting these engines to idle any quieter.

This power increase in the top end cuts in at around 4500rpm, when a special high-lift cam engages, allowing more air into the combustion chamber. And it is noticeable. Taking the Mako onto the plane and easing the throttle slowly forward past that mark on the tacho, there is a noticeable change in the ambient noise from increased air ingestion, along with an equally noticeable surge in power.

This VTEC system is mated with a dual-stage induction, which varies the throat of the intake manifold to suit the transition from standard running to when the VTEC takes over. Honda claims it maximises low-end torque, without compromising high-end horsepower.

Adding to increased economy is a function called Lean Burn Feedback, which offers 20 per cent less fuel consumption in cruise mode up to 4000rpm by adjusting the air/fuel mix according to speed and load on the motor at the time. This has got to be good for the hip pocket when coping with heavy seas at slow plane and when loaded up with skiers.

The installed Humminbird GPS was set in knots, but when converted, the Mako rocked onto the plane at 3300rpm and 18.5km/h, and settled into a cruise speed of 35km/h at 4000rpm. A WOT setting had the 150 humming at 6050rpm and 63km/h. This rig was nicely balanced and given the hull weight, the 150 was easily up to the job.

We next tested the BF50 remote control engine on a Quintrex 470 Freedom Sport. With two large adults aboard, it produced ample performance for this hull/motor combination, with the engine running typically quiet for this brand. Honda’s BF40, BF50 and BF75 models feature BLAST technology, which stands for ‘Boosted Low Speed Torque’. So, too, does the BF90, which is the lowest horsepower outboard with VTEC.

BLAST allows the air/fuel ratio to adjust in harmony with changing ignition timing in harmony with changing ignition timing for improved acceleration, which is noticeable with these models. It’s particularly effective during hole-shot and at those lower speeds where torque is required to carry heavy loads or drag skiers out of the hole.

The BF40 and BF50 are three-cylinder blocks with an offset gear to get the weight of the power head more forward over the transom. They offer lean burn control during sustained cruising of between 3000 and 4500rpm for further efficiency, and their light weight provides increased options due to a high boat weight/low engine weight for horsepower ratio. Honda claims a 1.0dB reduction in noise emission from these engines and a recyclable rate of 93.6 per cent. Now it is not often you see this type of statement, but it goes to show how we are evolving to minimise our impact on the environment, and how the management at Honda is thinking.

Next, we checked out the BF90, which was attached to a Mako 480 Tournament boat. This boat does actually work the bass tournament scene and rubs shoulders with the big guns in the form of Skeetas and the like, which run up to 250hp.

Without checking instrumentation, it’s reputed to run at around 75km/h at 5500rpm, while consuming 9.3lt/h. With BLAST, VTEC and Lean Burn Feedback under the lid, this was a snappy machine that had brilliant hole-shot and a top end that was not in doubt. It had the ability to trim the leg up to the maximum, while the hull remained flat on the water with no porpoising, which is the usual result with so much trim. This, and all other Honda engines in the range, are OEDA three-star rated.

Looking at the BF150 paired up on a Sailfish 2800 on the day, we noted impressive performance from these counter-rotating engines. Backing down and using throttles, they spin this big boat with ease and provide plenty of power for the cat hull. You have already read the nitty gritty on these engines, so performance-wise we can tell you they could get the Sailfish out of the hole in 1.9 seconds and keep her on the plane at 2800rpm and 25km/h. At a cruise speed of 45km/h, each engine was using 18.8lt/h at 4200rpm and on WOT it maintained a speed of 70km/h at 5600rpm.

A smaller Sailfish, the 2400, was also on hand, with a pair of counter-rotating BF135 engines. Honda has decided to leave off the VTEC technology on the BF135, but has included Dual Stage Induction (Variable Air Intake Manifold) and also the Lean Burn Feedback. Like the 2800 Sailfish, the 2400 is no lightweight, but these engines more than did the job. At WOT of 5800rpm the GPS indicated 72.5km/h, and at 5000rpm it registered 60km/h. At 4400rpm we noted just over 50km/h, and if you want to save on fuel, drop the throttles back to 3200rpm and you’ll loaf along at 35km/h, at which speed these engines are reputed to be burning 11lt/h each. You can’t complain about that!

Also on hand was a BF75 attached to a Stacer 489 Easy Rider. This boat is owned by Honda and apparently it is a scramble every Friday to see who gets to take it home for a weekend of family skiing. It apparently tows two skiers with ease and looking at the acceleration this engine affords through the use of BLAST technology, we reckon it could handle a triple tow!

With no instrumentation to check speed, it easily does well over 60km/h, but the hole-shot is both awesome and surprising. Other than VTEC, it sports all the features of the BF90 in a 1.5lt four-cylinder block with 16 valves and a double overhead cam. You can also option this engine with a tiller handle, if need be.

All up, there is a good spread of Honda outboards to consider, each with all the features we look for these days. For quiet running, low emissions and good fuel economy, Honda’s outboard offerings won’t disappoint.