RACE ENGINES Europe
Official agents for the Yamato Motor Co., Ota, Japan
Yamato Engine Chronology
It can be argued that country of Japan and their support of Kyotei pari-mutuel outboard boat racing literally saved stock outboard racing. In the mid 1970's new stock outboard motors were few and far between, with the bulk of the engines in use having been built in the mid-50's, it was difficult to generate new interest in the sport.
Enter the Yamato Corporation of Japan, and their exportation of the Yamato 80 engine into the United States. Almost overnight, racers and would be racers could buy a virtually new engine for $400-$500. The engines were run for about one year on the Japanese Kyotei circuit, sent back to the factory and sold refurbished as surplus around the world. The result was tthe introduction of the OSY.400 class (C Stock Hydro in the USA) of outboard racing, now the worlds largest motorboat racing category.
The Yamato 102 was introduced in the mid 1980's and the current Yamato version, the model 302, arrived about 10 years later. Today, Yamato 80's, 102's, 302's and even the occasional 202 can be found actively racing throughout the world in some of the most competitive classes.
Listed herewith are photos of the various engines which illustrate the progressive evolution of these engines through the years:
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Engine Model :
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Bore x Stroke :
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Weight (kg) :
YAMATO 30
March 1956
Regatta Promotion of Industry
325cc
2
62.0 x 54.0 mm
18.5 hp @ 5500 rpm
33.0
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Engine Model :
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YAMATO 60
May 1961
Yamato Engine Corporation
348cc
2
64.0 x 54.0 mm
20.5 hp @ 6000 rpm
36.5
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Engine Model :
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YAMATO 65-B
June 1967
Yamato Engine Corporation
348cc
2
64.0 x 54.0 mm
22 hp @ 6300 rpm
37.0
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FUJI KB-3
April 1971
Fuji Motorboat Corporation
345cc
2
64.5 x 60.0 mm
30 hp @ 7200 rpm
39.0
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YAMATO 102
May 1980
Yamato Engine Corporation
396.9cc
2
66.0 x 58.0 mm
30 hp @ 6400 rpm
40.0
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Engine Model :
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YAMATO 302
May 1995
Yamato Engine Corporation
396.9cc
2
66.0 x 58.0 mm
33 hp @ 6600 rpm
41.5
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YAMATO 331
Dec 2014
Yamato Engine Corporation
396.9cc
2
66.0 x 58.0 mm
32 hp @ 6600 rpm
41.5
Introduced in December 2014, the model 331 is the current motor racing in the stadiums.
It has been designed to reduce the number of serious accidents in the turns by reducing the power by 1hp - this has proved successful.
​
There currently no plans to replace this model.
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HP output / RPM :
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Weight (kg) :
YAMATO Y-1
March 1953
Regatta Promotion of Industry
325cc
2
62.0 x 54.0 mm
15 hp @ 5500 rpm
32.0
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YAMATO B-35
September 1956
Kinuta Internal Engine Factory
347cc
2
66.0 x 50.8 mm
20.5 hp @ 6200 rpm
33.0
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YAMATO 65
April 1965
Yamato Engine Corporation
348cc
2
64.0 x 54.0 mm
22.0 hp @ 6300 rpm
37.5
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YAMATO 70
December 1970
Yamato Engine Corporation
348cc
2
61.8 x 58.0 mm
28 hp @ 6400 rpm
41.0
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YAMATO 80
January 1974
World Motorboat Corporation
327.8cc
2
60.0 x 58.0 mm
30 hp @ 7000 rpm
40.0
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YAMATO 202
October 1985
Yamato Engine Corporation
396.9cc
2
66.0 x 58.0 mm
32 hp @ 6600 rpm
42.5
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YAMATO 321
Dec 2005
Yamato Engine Corporation
396.9cc
2
66.0 x 58.0 mm
33 hp @ 6800 rpm
42.0
Experimental Motors
Water-jet conversion Yamato motor
The experiment with nitrous oxide injection was not a success.
The prototype electric motor was abandoned following inconsistent performance during testing.