80s Tohatsu 2stroke 18hp Carb Questions - wierd external vacuum pump

backmarker

Cadet
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Sep 8, 2011
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16
I've got a Tohatsu 18hp which I am basically done restoring. The carb has an additional little vacuum pump attached to it, the diaphragms are toast, but I can't seem to find replacements, and I cant even find in the parts catalogues

Can I just blank off the connectors or can i fit a later model 18Hp carb, the newer carbs do not have this particular vacuum pump.

What is this thing supposed to do? thanks for the advice,
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Sea Rider

Supreme Mariner
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Sep 20, 2008
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12,345
Post a pic of the carb and front and rear diaphragms for better clarification. Newer 2 strokes 18 HP carbs have a vacuum fuel pump attached to the right side when carb is seen from the front. If both diaphragams match the size of your old carb can use them or cut to size if being smaller...

Happy Boating
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
It sounds like you may have a B18 model. Those had a separate fuel pump rather than one built onto the carburetor like the 18A and up series. I don't think they were ever imported into the U.S. No parts available at all and I think I'm one of two people who have ever seen one:)
 

racerone

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Perhaps it is a " dashpot "-----Post a picture of this item.----How many hoses go to it ?
 

backmarker

Cadet
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Sorry for the belated response I was away for our summer holidays
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backmarker

Cadet
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Sep 8, 2011
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the carb has a fuel pump connected to it on the other side, this seems to be the vacuum system
 

Sea Rider

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That's a very oldie carb, newer 2 strokes 18 carbs are much simplier and compact. Will have my doubts if possible to be screwed to manifold..Going back to the original post, are you in need of new diaphragams located inside the square black box ?

Happy Boating
 

backmarker

Cadet
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Sep 8, 2011
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Hi Sea Rider, ! Yes thanks. I'm thinking to get newer model carb, and manifold will solve the problem.
unfortunately a very $$$ exercise. I just had the power head reconditioned. So I suppose I have to follow through.

The Yamaha 15hp used the same carb as the Tohatsu 18C2, so it might be easier to find a used one here in South Africa swop the jets out and get a later model 18c2 up manifold
 

Sea Rider

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Sep 20, 2008
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12,345
Maybe Paul or TG could guide you in the correct direction. Only work with the newer M18E2 models. Will need to check oldie 18 HP versions parts manuals to check if possible to swap other manifold and carb to your current model.

Happy Boating
 
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