Tohatsu/Mercury 3.5hp main jet size?

Nos4r2

Nos4r2

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Hi all,

I've got a 1981 2.2 Mercury here and as far as I can make out it's exactly the same powerhead as the Tohatsu/Nissan 3.5 hp apart from a different mainjet size and a restrictor in the carb throat.

I've removed the restrictor and readjusted it so the throttle is opening fully.

However,my nearest Tohatsu dealer is a long way away and about as much use as a chocolate teapot, so hopefully I can get a new mainjet from our local bike shop.

Does anyone know what size the 3.5 mainjet is?
 
Sea Rider

Sea Rider

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Re: Tohatsu/Mercury 3.5hp main jet size?

Main Jet is 86 for 2.5/3.5

Happy Boating
 
Nos4r2

Nos4r2

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Re: Tohatsu/Mercury 3.5hp main jet size?

Thanks Sea Rider :)


I wonder why it's wheezing and sounding rough with the restrictor plate out if they are both the same size mainjet? It seems ok with the restrictor plate in. Air leak perhaps...
 
Sea Rider

Sea Rider

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Re: Tohatsu/Mercury 3.5hp main jet size?

Is the jet needle that lives inside the throttle valve, well adjusted to match the 3.5 model setting ? The needle's position can be changed by moving the jet needle clip, which position is it locked in ?

Happy Boating
 
Nos4r2

Nos4r2

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Re: Tohatsu/Mercury 3.5hp main jet size?

TOHATSU GURU said:
You basic premise is flawed...
Click to expand...

Which part of it? Is it a different powerhead?



Sea Rider-I don't know if the needle setting is correct either. Do you know the setting for the 3.5?
 
Sea Rider

Sea Rider

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Re: Tohatsu/Mercury 3.5hp main jet size?

It's 2nd from bottom for Tohatsu 2.5 & 3.5 carbs. Carb must be completely vertical. Replace carb's big black o'ring if found sealing defective.

Happy Boating
 
Nos4r2

Nos4r2

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Re: Tohatsu/Mercury 3.5hp main jet size?

Thanks :)

I'm still wondering why TG says my basic premise is flawed.
 
Nos4r2

Nos4r2

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Re: Tohatsu/Mercury 3.5hp main jet size?

pvanv said:
Because it's not a jet change -- it's a different carb.
Click to expand...

Thanks-makes sense now.

Out of interest, why the restrictor plate then?
 
pvanv

pvanv

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Re: Tohatsu/Mercury 3.5hp main jet size?

There isn't any restrictor on a Tohatsu-labelled motor. Might be to restrict it down from 2.5 or 3.5 to 2.2 for Merc.
 
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