The first outboard motor was made by Ole Evinrude, a Norwegian-American, in 1909.
Until recently, most outboard motors were two strokes. These engines were fitted with a carburettor and the design was fairly straight forward and simple. Nowadays, with all the emphasis on reducing pollution, two strokes are considered too heavy on unburnt hydrocarbons for todays’ world.
During the mid 1990s European directives and US exhaust emission laws made manufacturers change from two to four stroke engines. All the main marine outboard engine companies have now developed new four-stroke motors. Most of these new engines are fuel injected apart from the smaller outboards, which still use carburettors. Some models benefit from variable camshaft timing, and multiple valves per cylinder. Mercury Verado four-strokes are unique in that they are supercharged.
Mercury outboard motors have an interesting history. They were started by an engineer, Carl Kiekhaefer, who sold them at first, by mail order. The outboards were so well made- they withstood extreme conditions better than any other motors – buyers soon were purchasing massive quanities. Nowadays, Mercury also produce Mariner outboards (outside the USA).
Mercury, Tohatsu, Yamaha and Evinrude each developed computer-controlled Direct-Injected two-stroke engines. Each brand boasts a different method of DI. Fuel economy on both direct injected and four-stroke outboards has been vastly improved.
Evinrude, founded by the inventor of the outboard motor, are a major name in the marine industry. They became connected to Johnson outboards when they were bought by Outboard Marine Corporation (OMC). Now both are owned by Bombardier Recreational Products. When both these major names were acquired, their technology was updated and E-Tec direct fuel injection was introduced. They were the first to win the American EPA 2005 Clean Air Excellence Award, which recognises low emission levels from outboard engines. The EU now also recognises this as well.
Honda first produced outboards in 1964. They have been making four-stroke engines ever since.
Suzuki started making outboards in 1965 as an extention to their cars and motorcycles.
British Seagull outboards were produced from the 1930s until the 1990s. The previously mentioned exhaust emission regulations put them out of business, as a manufacturer. However, the company still operates as a replacement parts business. Which is just as well, for these engines go on for ever and ever. Even the original ones made in the 1930s are still going! They are a strange outboard motor. The models are all named after the power in pounds per thrust that they produce. For example, the smallest, called the ‘forty minus’ gives out just less than 40pounds of thrust. This particular outboard – just to confuse you – is also called the ‘featherweight’. The largest engine, the ‘silver century plus’ produces over 125 pounds of thrust. Although pretty primative looking these outboards can push a fairly heavy displacement boat of, say 25 feet long.
This gives you a brief look into the history of outboards. A considerable amount more could be included but this gives you an overview of the main companies.