Tohatsu 30hp four-stroke

By fitting larger diameter carburettor jets and slightly raising the Wide Open Throttle rev range to its MFS 25A, Tohatsu Corporation has created a 30hp four-stroke that is, in reality, much more powerful than the additional 4.9hp would suggest.

But what really sets this motor apart from its four-stroke competition is the combination of its light weight and power trim and tilt. For example, the electric-start longshaft Honda BF30 weighs 72kg but is available only with manual trim/tilt, while with power trim and tilt the Yamaha F30A weighs 91kg and the Mercury F30 96kg, mainly because the latter motors are de-rated from their 40hp counterparts.

When mounted on small forward control runabouts (about 4.2m), the F30A and F30 create no real trim problems because the helmsman and passenger weight compensates for the outboard on the transom. But mount them on a small side-console bass boat where the helmsperson and passenger weight is biased aft and it's a very different story!

In July I tested an MFS 30A on a Stacer 420 Proline Angler fitted with a sports side console and supplied by In Tune Marine of Long Jetty NSW. Admittedly the bow-mounted Minn Kota electric motor helped balance the hull, but the console was aft of amidships and the helm seat just ahead of the aft casting platform, which contained the battery and a 25-litre fuel tank. Combined with the passenger seat amidships we really needed power trim to plane us.

Spinning an 11in Tohatsu alloy prop and pushing a total of 600kg including two adults, the demo MFS 30A trolled quietly at 4.0kmh on 900rpm using 0.5lt/hr. But to plane the hull my co-tester Dave Denny from Lakeside Marine had to sit on the forward casting platform, and even then WOT was needed to get us up with a minimum plane of 18.0kmh at 3800rpm. And when Dave sat on the passenger seat amidships we needed 4000rpm and 21.9kmh to achieve a clean plane. At these revs the motor was working pretty hard and consumed 5.2lt/hr.

Increasing the revs to 4500 substantially reduced motor load. We cruised quietly at 30.1kmh using 5.0lt/hr, while at WOT over a slight chop we averaged 44.4kmh on 5900rpm consuming 10.2lt/hr.

Through tight figure-eight turns at WOT there was no prop ventilation and across the entire rev range vibration levels were lower than the F30A and F30 tested on similar-size tinnies.

As with its MFS 25A counterpart, the automatic choke ensured instant starting hot or cold (whether we used the starter motor or manual recoil starter) without having to worry about what amount of choke to use or how far to raise the neutral warm-up lever. No oil smoke appeared at any time and after about five minutes in the 12-degree ambient temperature the motor had reached normal operating temperature. Providing the anti-ventilation plate was kept immersed, power astern was very good and the rapid trim/tilt system provided almost instantaneous trim changes.

Back at Lakeside Marine on completion of trials, a nice touch was the screw-in flushing facility that connects directly to a garden hose. When the water is turned on, the powerhead cooling water passages are filled and water reaches the water pump impeller to ensure it doesn't run dry. Much easier than using rabbit ears or a flushing drum!

The MFS 30A has the same rev limiter (6500) and low oil pressure reduction of revs to 2800 as its 25hp sister. Although the starter motor and its associated wiring does reduce powerhead access, it's still very good. The oil dipstick and spin-on oil filter are easily reached, but as with the 25hp, Tohatsu has not fitted a bowl-type fuel filter. That's odd - the two-stroke 30hp has one.

The sump has sufficient capacity to absorb any oil 'sludging' between changes and recommended servicing intervals are every 50 hours, or six months after the initial 10 hour/one month service and the water pump impeller should be replaced every 100 hours or yearly.

The warranty provides two years of coverage for recreational applications.