Choosing an outboard motor for your boat
30 years ago, American manufacturers dominated the outboard market, names like Mercury, Johnson, Evinrude and Chrysler led the field competing with each other to produce bigger and better outboards. However, while this was going on, they were neglecting the smallest of outboards. These are the highest-selling outboards and are often the first outboards many of us buy. With this being the case, many of us stick to the same brand (brand loyalty) while purchasing larger outboards over the years. The Japanese took advantage of this fact and gradually Honda, Yamaha, Suzuki and Tohatsu, which were concentrating on small outboards, began to take over as market leaders. They achieved this mastery by improving efficiency and reliability. As well as adding features to these little outboards that were previously only found on larger engines.
Having achieved success in the small outboard market, these Japanese manufacturers expanded the power range. Again they came to dominate the market for outboards up to at least 20 hp. The American manufacturers, instead of competing with the Japanese, gave up and decided to buy these engines from the Japanese and brand them as their own. Now the Chinese have entered the market. Basically doing what the Japanese did before, copying the best features of current engines while keeping costs low.
So let’s compare the outboards offered for those who are looking for an outboard motor for their boat. If we take a rather larger boat, say, a Pioner 12, so that each outboard has to push a reasonably heavy weight through the water. If then we take the following outboard motors:
Mercury 2.5 hp; Mercury 3.5 hp; Marinate 2.5 hp; Tohatsu 3.5hp; Yamaha 2.5hp; 2.5 hp Suzuki; Honda 2.3hp; and a Parsun 2.6hp. All of these outboards are 4-stroke engines. This is due to an EU directive that prevents 2-strokes from being sold in the EU. These outboards will provide a fairly wide range of commercially available engines to power boats.
To judge one engine against another, several tests were carried out. A Bollard pull test showed the Mercury 3.5hp and Tohatsu 3.5hp to be the most powerful with 90 pounds of thrust (these two engines along with the Mariner are practically identical). The least effective was the Honda 2.3hp with 66 pounds of thrust. In the middle were the Suzuki 2.5hp at 83lbs of thrust, the Yamaha 2.5hp at 78lbs of thrust and the Parsun 2.6hp at 70lbs of thrust.
The next test was fuel consumption. At full speed, 5.75 knots, the best outboards were the 2.5hp Yamaha and the 2.5hp Suzuki by at least 20%. The worst was the Parsun 2.6hp. When the throttles were loosened and the boat was sailing, the fuel consumption comparison was less obvious, only about 10% difference. All these figures are for 4-stroke engines. However, based on previously recorded 2-stroke figures under similar circumstances, older engines were up to 50% less fuel efficient at full speed. Very thirsty! Remember that 2-stroke outboards are still available second hand.
The weight of each outboard motor was then compared. Four-stroke engines are heavier than older 2-strokes due to the power head, etc. The Mercury, Mariner, Tohatsu, Yamaha and Parsun weighed approx. 38 – 41 pounds (18 kg). However, the Honda 2.3hp and Suzuki 2.5hp weighed much less at 28 pounds (12.5 kg).
The price of each outboard was then compared. This was difficult to be exact as discounts and sales offers always change.
Mercury 3.5hp € 449
Mercury 2.5hp £ 380
Marinate 2.5hp € 499
Tohatsu 3.5hp € 449
Yamaha 2.5hp 549 €
Suzuki 2.5hp € 379
Honda 2.3hp 499 €
Parsun 2.6hp 375 €
Although the Parsun was the cheapest and is practically identical to the same engine as the 2.5 hp Yamaha, it is not that good. It’s a bit like I’m following a Gordon Ramsay recipe, verbatim, but when you compare them side by side, you know yours is going to be so much better. The Chinese can copy, just like the Japanese before them, but they haven’t gotten it right yet!
Finally a bit about each tested outboard motor. Mercury, Mariner and Tohatsu are the same engine. Start settings for the throttle are easy to understand with clearly labeled choke and stop button. The fuel on / off tap is not so clearly marked. All of these motors have gears. Forward and neutral, then using 360 degree rotation, you can get a push back. There are 4 tilt positions and shallow water capability. Oil levels can be easily checked by looking at the gauge on the side of the engine cover.
The Yamaha 2.5hp also easily understood the start and stop settings, but the oil level gauge was out of sight under the engine housing cover. As with the Mercury outboard motor, the Yamaha 2.5hp has forward and neutral gears with 360 degree rotation. Unlike the Mercury, which has a shear pin, the Yamaha has a rubber hub on the propeller, so there is no shear pin to break off.
The Suzuki 2.5hp is like the previous one, but with the oil gauge it is easily seen on the side of the cover. The propeller has a shear pin with spares stored under the engine cover.
The Honda 2.3hp is not water-cooled like all the other outboards tested. It is air-cooled and has no gears. Instead, use a centrifugal clutch. This makes starting and maneuvering more difficult than the others. It just takes a little getting used to. The oil gauge is out of sight under the cover. The propeller has a spare locking pin under the engine cover.
Finally the Parsun 2.6hp, a copy of the Yamaha 2.5hp but not so good. However, it is the cheapest engine when new. Fuel consumption was its biggest drawback.