Facts
The outboard engine is a very common mean of small boat propulsion
system. It consist of the engine itself, the power transmission
(gearbox), the propeller, the mounting system, and on smaller units,
the incorporated fuel tank. The main function is of course boat
propulsion, but it is used also for steering, since it can rotate on
the mountings. It is installed on the transom of the boat.
It offers several advantages over the traditional inboard engine:
- it is easier to install
- the engine, gearbox and propeller are well matched (they have to be
matched to the hull too)
- it can be tilted, which allows usage it in shallow waters and to
reduce the effects of fouling
It is used mostly for smaller, recreation boats, but lately some
brands produce units in power ranges that can fulfill the needs of
bigger crafts.
Trends
From the beginning, they were mostly small units, with one cylinder,
few horse powers and an included fuel tank. Soon, bigger units
appeared, with more cylinders, separate fuel tank, remote controls,
electric current generator and greater power.
They were regularly 2-stroke engines, because of the simplicity,
reliability, lightness and higher specific power of the 2-stroke
engines. On the downside, these engines had higher specific fuel and
oil consumption, and higher emissions, especially unburned
hydrocarbons, compared to 4-stroke engines. But fuel price and
emissions were not a problem at the time at the beginning of the 20th
century. In the late sixties, Honda started to build 4-stroke
outboard engines. Later, in the nineties, increasingly stringent
exhaust emission limits, especially in the US and Europe, forced all
the producers to the 4 – stroke cycle technology. These engines
have lower emission levels, fuel consumption, and smoother operation.
However they are heavier and more complex then the 2-stroke
alternatives.
In the first years of the 2000s, Evinrude came with the E-TEC direct
fuel injection system applied to their range of outboard engines.
They gained the favor of the public and some media, since they claim
to achieve the best of the 2 worlds: 2 and 4 stroke technology.
Brands
The
outboard engine has been around now for more than a century. The
first commercially
available gasoline fueled
(there were some
electric before) unit seem to be the 1906 - Waterman Porto.
Seagull
A legendary design and brand is the British Seagull, produced in
England from 1931 to the mid 1990-ies. It' simple design allowed a
great reliability and the engines gained many fans. Many of them
still run and are actually used. Details about the engines and their
history can be found on several Internet sites. At the end of the
century it ended its production because of the ever more restricted
emission laws, which the 7 decades technology could not fulfill.
http://www.saving-old-seagulls.co.uk/index.html
Tomos
In my region, the former Jugoslavia, Tomos was the most famous, and
often only brand. It was founded in 1954 in Sežana, Slovenia. The
factory was soon transferred to Koper, where it started a licensed
production of small motorcycles. The outboard production started in
1959 when the Lamo 05k model was released. It was a one cylinder, 50
ccm, air cooled engine that could deliver 3 hp, with the fuel
consumption of 0.9 l per hour.
Later during the sixties more advanced models were developed, with
water cooling, enhanced reliability and power. They had the
displacement of 59.4 ccm and power between 3 and 4 hp. At the
beginning of the seventies, the two cylinder models were developed:
the Tomos 10 and 18 had the displacement of 250 ccm, and they
delivered 7,3 kW at 4000 - 4600 rpm and 13 kW at 5200 - 6000 rpm.
The production ended with the separation of Jugoslavia at the
beginning of the nineties.
Detailed information on Tomos history can be found on:
Japan is the country with the biggerst number of outboard brands.
Honda has been manufacturing four-stroke outboard engines for over 50
years, which makes them leaders in low emissions. They produce
engines divided in 3 ranges: Portables (from 2.3 to 20 hp), Mid range
(25 to 100 hp) and High power (115 to 250 hp).
Suzuki Produces 4-stroke outboard engines in 4 ranges: Portables (2.5
to 30 hp, carburated or EFI – Electronic Fuel Injection), Mid size
(40 – 60 hp), In-line 4 (70 – 200 hp) and V6 (225 -350 hp).
Yamaha produces many ranges of 4-stroke outboard engines that really
cover all the needs.
- 2.5, 4, 6 hp, single cylinder, carbureted, portable
- 8 – 25 hp , 2- cylinder, lightweight, electronic fuel injection
- 30, 40 hp, 3-cylinder, 750 ccm
- 50, 60, 70 hp, 4-cylinder, 1000 ccm
- 75, 90, 115 hp, - 4-cylinder, 1.8 l displacement
- 150, 175, 200 hp, 2.8 l displacement
- 200 hp, V6, 3.3 l
- 225, 250, 300 hp – V6, 4.2l
- 350 hp, V8, 5.3l
-XTO Offshore - 425 hp, V8 5.6l
Besides, they offer the high tech and performance V Max SHO (Super
High Output) line, and claim leading torque, speed, and efficiency:
In-line 4: 90, 115, 150 and 175 hp
V6: 200, 225, 250 hp
https://yamahaoutboards.com/en-us/
Tohatsu began manufacturing outboard engines in 1956 and is Japan’s
oldest outboard manufacturer. Outboards were originally developed for
commercial Japanese fisherman.
Today they divide their program in 3 ranges. Beside the prevailing
4-stroke units, they offer 2-stroke engines and also LPG powered
4-stroke. Some models have direct fuel injection (TLDI models). There
are also some models called Ever Run, which are claimed to have
superior reliability.
Portables: 20 hp, 18 hp, 15 hp, 9.9 hp, 9.8 hp, 8 hp, 6 hp, 5 hp, 4
hp, 3.5 hp and 2 (2.5) hp
Mid-Range: 100 hp, 90 hp, 75 hp, 60 hp, 50 hp, 40 hp, 30 hp and 25
hp
High Power: 250 hp, 225 hp, 200 hp, 150 hp, 140 hp and 115 hp.
https://www.tohatsu.com/int/
Mercury
The main American brand is Mercury, located in Fond du Lac,
Wisconsin. The first Mercury outboard was manufactured in 1939.
Verado: 250 and 300 hp (V8, 4.6 l displacement), 350 and 400 hp
(Inline 6, 2.6 l displacement, supercharged), direct fuel injection
Sea Pro: adressed to the professionals who demand higher reliability,
models from 15 to 300 hp, from single cylinder to V8 models.
Four Stroke: dedicated mostly for recreational users, 2.5 to 300 hp
models, from 1 cylinder to V8 models, the smallest are carburated,
while the biggerr have the EFI (Electronic Fuel Injection) system
ProXS: the high performance line. It replaces the OptiMax line of two
stroke direct fuel injection engines. It offers more power per weight, higher
speed and acceleration then compared to the Four Stroke series. The
technology used is derived from racing models and they rely on higher
rpm. The power ranges from 115 to 300 hp.
https://www.mercurymarine.com/en-gb/europe/
Evinrude
An outboard named Evinrude after its constructor exist since the
1909. However, the brand name was owned by various owners. In a
period it was Johnson, another American outboard brand. In the year
2000 the company was pushed into bankrupcy. In 2001 it was aquired by
the Bombardier group. The Evinrude main site is located in
Sturtevant, Wisconsin.
Their bigger models ( not tehe Portables) are characterized by
two-stroke technology and direct fuel injection. They claim that it
allows them superior torque, pawer to weight ratio, lower consumption
and emissions than the competitors.
Portables: 3.5 – 15 hp
E-tec: 25 – 135 hp
E-tec G2: 150 – 300 hp
There are some other very interesting niches in outboard market, like
the diesel fuelled OXE and Yanmar/Neander 50hp Dtorque 111, the
electric powered Torquedo, the LPG powered Lehr. There are also some
competitive Chinese alternatives to the mentioned mainstream production,
especially in the lower end production. We could mention here the
luxuary niche promoted by the American 7-Marine. However, theese
occupy smaller market niches. I could possibly write about them in a
future post.
