Tohatsu BFT150A outboard motor review

Midway in the Honda/Tohatsu range of four-stroke outboard motors from 60 to 250hp, the Tohatsu BFT150A is based on the Honda Accord Euro car engine that can deliver up to 197 brake horsepower (bhp) at 7000rpm. So in its marine form, it’s way under-stressed. And though it has the smallest piston displacement of all 150hp outboard motors, its low-speed to midrange fuel efficiency is closer to that of a comparable direct fuel injection two-stroke outboard than a four-stroke

The OEDA 3 StarTohatsu BFT150A outboard motor develops 147.9 propshaft bhp at 5500rpm, with a Wide Open Throttle range of 5000 to 6000rpm. Its four-cylinder DOHC 2354cc powerhead has chain driven camshafts and twin counter rotating balance shafts, but oh so simple valve clearance adjustment where only a feeler gauge and 10mm spanner are needed for the 16 valves.

At 40amp the voltage regulated alternator is adequate for onboard electronics, though a fair proportion of this is used to run the sequential multipoint electronic fuel injection. But unlike the non-Honda competition the 150 has an oxygen sensor in the exhaust that alters the air/fuel ratio according to fuel density. So if you use premium (95 RON) unleaded the ignition timing will advance resulting in more torque and power.

The Tohatsu 150 outboard has all the features of its BFT60A counterpart, such as BLAST* for faster holeshot and ECOmo* for lean-burn cruising, but differs in that variable air intake and VTEC (or rather, VVT & LC* to use the correct term) are also fitted. Below 4000rpm the air travels farther from the intake box to intake valves, resulting in more torque down low. Above 4000 the air intake passage is shorter resulting in more top-end power. And at 4500rpm VTEC holds the intake valves open longer for better breathing, resulting in an engine that just loves to rev.

The Tohatsu 150 outboard has a usefully low 2.14:1 gear ratio and a dry weight of 220kg for the extra-long-shaft version.

Powerhead access is excellent, with the sump oil dipstick and canister oil filter easily reached. The massive 6.7lt sump has the capacity to absorb oil dilution from piston ring blow-by during extended trolling and the recommended oil is FCW SAE 10W30 for all but extreme tropical climates. Servicing intervals are every 100 hours or annually after the first 20 hours and the recreational warranty is three years.

* Note: these are registered trademark of Honda Motor Co.,Ltd. The formal name for VTEC os VVT & LC).

PERFORMANCE

How nice to have a test hull fitted with maximum power! The Stejcraft 580 BR Bahama bowrider is rated from 90 to 150hp or a maximum outboard weight of 250kg, so the review BFT150A engine was a perfect match for our total displacement of 1400kg, including Lakeside Marine’s Dave Denny, myself, test gear and 100lt of PULP.

Dave went to a lot of trouble to set-up the 580 for wakeboarding and top-end performance and finally settled on a 17in pitch Solas four-blade stainless steel Titan prop that allowed the 150 to rev well out.

As expected the 150 started instantly hot or cold with no oil smoke and had an almost total lack of engine vibration across the entire rpm range. Once the engine was warmed up, slamming down the throttle lever from trolling rpm planed us in just 3.4 seconds, with another 16.7 seconds to reach terminal velocity. Flooring the throttle from 4000rpm took 12.4 seconds out to WOT. Through tight turns at 4000rpm there was no prop ventilation.

Best of all was the engine’s quiet running at or near WOT. Dave and I could talk at the helm without raising our voices, making the whole test experience just that bit more enjoyable!

THE TRADE-A-BOAT VERDICT

Though it doesn’t have the sheer grunt of its bigger displacement competition, on the right hull the BFT150A will show up even the DFI two-stroke competition. Tohatsu Corporation has been very clever in working with Honda to create a total power package that with a bit of TLC will provide years of on-water pleasure. But don’t expect it to reduce flab!

As of March 2014 the Tohatsu BFT150A had a price of just over $21,000 with a spare Titan for around $800. Thanks Dave and Lakeside Marine – Charmhaven-NSW, phone (02) 4392 6110 – for such a well setup demo rig.

TOHATSU BFT150A OUTBOARD MOTOR SEA TRIALS

Single 147.9hp Tohatsu BFT150A outboard motor. Average of two-way runs on low chop using Doctor H fuel-flow gear and handheld GPS

* Same fuel flow due to less engine load when fully planning. Sea-trial data supplied by the author.

NATURALLY-ASPIRATED COMPETING OUTBOARD MOTORS

TOHATSU BFT150A OUTBOARD MOTOR SPECIFICATIONS

TYPE Four-cylinder four-stroke petrol outboard motor

RATED HP 147.9

REC. RPM RANGE 5000 to 6000

DISPLACEMENT 2354cc

BORE x STROKE 87 x 99mm

WEIGHT 220kg (XL)

GEAR RATIO 2.14:1

PRICE $21,000

WARRANTY 3 years

OEDA STARS 3

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See the full version of this review in Trade-A-Boat #457, September / October 2014. Why not subscribe today?