Saturday 16 May 2015

Oddball Engine: 1971 Tohatsu Sea Swallow B9A

Today the Petrolist is bringing you a real odd little engine. It's a 1971 Tohatsu Sea Swallow, model name B9A.
It is one cylinder, air cooled (!), 5 hp. Has a traditional F-N-R gearbox.
I have seen a few for sale here in Finland, but there seems to be close to no info available on the internet, so if anyone knows anything about these engines please come forward!

This engine was given to me by the neighbor at my GF's summer cottage. He saw my HD-26 and JW-16 that I brought with me the last time we went there, and was so impressed by my work that he wanted to give me this engine (not bragging, I felt quite flattered!). It's in an overall good condition, seems not to have been run that much, it only really needs cosmetical work. But it is in a surprisingly good shape considering that it had sat outside for the last five years!
Immediately when I got it I started to tear it apart. Found that it had good compression and even spark, which is always nice. I cleaned the carburetor and it fired after just a couple of pulls! Luckily I cleaned the carb before trying to start it, since the carb was completely gummed up with something unidentifiable.










As you can see, the lower unit and prop is the parts that need most cosmetic attention.



Not only do you learn about different engines, you also learn different languages!
Apparently, those signs mean "choke on" and "choke off" in Japanese.

















6 comments:

  1. Do you have a workshop manual for this motor please

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  2. I have an original workshop manual for this motor. I have recently been given one of these motors as well and it came with the book. What info do you need?..it doesn't give spaek plug gap only plug type but has all other info and diagrams.

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    1. Johnjardine@bigpond.com9 September 2023 at 17:08

      I have just bought a Sea Swallow to use when I am in the inlet and the river. I would love to some how get a copy of the manual if that is in any way possible. I have not had a chance to be sure yet but I am told that yes the motor is air cooled but the lower end of the unit including the muffler is water cooled.

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  3. Hi I also have onen, buts my one is called B9, It's 5hp and have the same coolar thins as yours, but to my surprise when I first started it in water to day it came a water beam, o I was lucky I did not brake the impeller or even the whole engine. I dont want to brag, but mine looks so fine I thought it was a mid 80's maschine, but dunno how low thay where in production. It Would be so cool do If you could fix me one of your copies, mutch work, but cool. Have you tried your in water yet, and are you 100 sure its only air-cooled, thoose thins tricked med =) Would be so greatful if you mail me, have som questions. I gues u see my mailadress but maybe closed to others.. thanks and bye!

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  4. Hello ! Please provide a link to the manual for this motor.

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