Suzuki DF6

In my opinion, Suzuki's DF6 is the best value 6hp outboard on the local market. And with the reduction in RRP as of January due to the strengthening Australian dollar, it's now significantly cheaper than its nearest two-stroke competition, the Johnson 6hp.

The DF6 is the only single-cylinder outboard I've tested - two- or four-stroke - that's capable of planing my Sea Al 3.6m dinghy with two adults and fishing tackle. And although it can't match the Johnson 6hp on this hull for outright performance, it's much more fuel efficient.

For example, spinning the standard 7in-pitch prop and pushing a total of 285kg, the DF6 trolled at 4.6kmh on 1260rpm using 0.2lt/h, whereas spinning a 9in-pitch prop and pushing the same total displacement, the Johnno averaged 3.2kmh on 750 revs using 0.5lt/h.

At Wide Open Throttle the Suzy averaged 23.4kmh on 5350rpm using 2.6lt/h compared to 27.3kmh on 5090rpm and 3.6lt/hr for the Johnno, so the additional displacement of the latter's 164cc twin-cylinder powerhead did make a significant difference here.

Across a "loop" of 10 per cent WOT and 40 per cent trolling operation at an average distance of 7.5km, the Suzy consumed 0.68lt/h compared to 2.0lt/h under identical conditions for the Johnno.

But the best performance from the DF6 has been on my Sea Jay 3.4 Punt, which I bought last June to combine with the Suzy to create a stable, easy-planing and fuel-efficient shallow-water fishing rig.

One of the few flat-bottomed punts currently available, the all-welded 3.4 has six transverse frames with rubber backing to reduce the harmonic vibration transmitted through the hull when using single-cylinder outboards. As a result, the vibration levels are less than those on my welded and riveted de Havilland John 10ft punt, and are comparable to the Johnson 6 on the all-welded Sea Al!

Again spinning the standard prop but pushing a total of 270kg, the Suzy trolled at 4.3kmh on 1220 revs using 0.18lt/h and achieved a clean plane at 20.4kmh on 4700rpm and half throttle. The WOT average was 30.2kmh on 5910rpm using 2.5lt/h, and across the same 7.5km loop the Suzy used 0.45lt/h.

Since January 2003 the demo DF6 has clocked up a total of 33.6 hours with 7.5 per cent WOT operation. The engine was run for a period at WOT during every on-water test to reduce the possibility of oil sludging in the sump, which can occur with all water-cooled four-strokes due to the relatively low operating temperature compared to their automotive counterparts. To run a four-stroke outboard at 90-100C would result in rapid accumulation of aluminium chloride (salt) crystals in the cooling-water passages, so the thermostats are normally set to open no higher than 70C.

The DF6 has averaged much better fuel/oil ratios and in a much shorter time than an air-cooled four-stroke such as Honda's BF2D, and using Quicksilver SAE10W30 oil from new, the oil consumption has diminished rapidly since the first service at 18 hours.

Up until this period, averaging 0.69lt/h with 7.5 per cent WOT operation, the DF6's fuel to oil ratio was 885:1 - but from 18 to 33.6 hours averaging 0.45lt/h and the same WOT percentage, fuel to oil ratio was 1410:1. This gives a total average for the 33.6 hours of 0.58lt/h and 1023:1 with 7.5 per cent WOT - an excellent result for a small water-cooled four-stroke.

To put that into perspective, a few hours of fishing will cost you less than a dollar in fuel.

Oil smoke appeared only once when the engine was cold - a result of the engine having been transported for some distance on its side.

After a total of 178.2 hours of saltwater leg and lower unit immersion, corrosion appeared limited to slight surface rust on one of the lower cowl retaining rivets. The lower zinc anode was about one-third eroded and the upper anode had slight surface etching, while the propeller shaft was completely unblemished.

Suzuki's DF6 has convinced me there's no logical reason to buy a small two-stroke outboard when you can have an engine this good!