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:

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • 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

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 60

May 1961

Yamato Engine Corporation

348cc

2

64.0 x 54.0 mm

20.5 hp @ 6000 rpm

36.5

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 65-B

June 1967

Yamato Engine Corporation

348cc

2

64.0 x 54.0 mm

22 hp @ 6300 rpm

37.0

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

FUJI KB-3

April 1971

Fuji Motorboat Corporation

345cc

2

64.5 x 60.0 mm

30 hp @ 7200 rpm

39.0

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 102

May 1980

Yamato Engine Corporation

396.9cc

2

66.0 x 58.0 mm

30 hp @ 6400 rpm

40.0

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 302

May 1995

Yamato Engine Corporation

396.9cc

2

66.0 x 58.0 mm

33 hp @ 6600 rpm

41.5

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

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.

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • 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

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO B-35

September 1956

Kinuta Internal Engine Factory

347cc

2

66.0 x 50.8 mm

20.5 hp @ 6200 rpm

33.0

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 65

April 1965

Yamato Engine Corporation

348cc

2

64.0 x 54.0 mm

22.0 hp @ 6300 rpm

37.5

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 70

December 1970

Yamato Engine Corporation

348cc

2

61.8 x 58.0 mm

28 hp @ 6400 rpm

41.0

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 80

January 1974

World Motorboat Corporation

327.8cc

2

60.0 x 58.0 mm

30 hp @ 7000 rpm

40.0

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

YAMATO 202

October 1985

Yamato Engine Corporation

396.9cc

2

66.0 x 58.0 mm

32 hp @ 6600 rpm

42.5

  • Engine Model :

  • Production Year :

  • Manufacturer :

  • CC Displacement :

  • Number of Cylinders :

  • Bore x Stroke :

  • HP output / RPM :

  • Weight (kg) :

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.