Carburettor Tohatsu MFS 3.5B

Hello,
I am new to this forum and not the expert with outboard engines, so I hope I can find some help here.

I have bought a 9 years old, little used Tohatsu MFS 3.5 with my sailing boat and I have a little bit problems with the motor. Starting is often difficult, the power is not really as expected (and getting weaker), especially when the engine is warm. I have tried to clean the carburetor, that helped a little bit. But not for al one time. For me, it looks like somebody else have already tried to „repair“ the carburettor, because some parts look a little mit scratched/damaged to me. After stopping the engine, there is immediately coming fuel out of the engine, so I think the little plastic box swimming in the carburator is not ok anymore. Sorry for the bad explanation, English is not good enough and I don’t know enough about carburators.

I think the best idea for me as a „newbie“ will be to change the whole carburator, not to try to repair it. And I think it is even cheaper to buy a new carburator, instead looking for a service / outboard repair, here in the Caribbean they offered me a price app. 100-150 US-$ just to „check and clean“ the Engine, with no parts changed. So I think a new carburator will cost the same - or even less.

I have found the very expensive original carburator (180 US-$), and this replacement at amazon, saying it will work for the 3.5 MFS as well.

https://www.amazon.com/-/de/dp/B07XZ6GBX8

Anybody here that can confirm I can. Use this carburator? That would be great!

So, I assume your model is MFS3.5B.
The carb is clearly flooding if fuel is dripping.
What method did you use to clean it?
Assuming that is your model, the correct carburetor is:

The description in that Amazon ad is wrong; The MFS4/5/6 does not use that carburetor. I think it would be a mistake to get that one. The seller clearly does not know what it fits, and is guessing.

At worst, get a new needle for your present carb, or adjust the float.

Hello Paul,
thanks for your answer. Yes, I have the Tohatsu 3.5B. And Thank you that you confirmed that the carburator for the 4/5/6 is another model, so I will not buy the amazon model.

I have once cleaned the carburator (one year ago, an dedicated outboard-spe******t/repair shop in France) with ultra-sonic. A couple of months ago, I have just used some solvent. There was a little bit dirt from old gasoline (5 months winter without emptying the engine/the carubaror).

And yes, the carb is flooding. The engine is running, but less power than normal. And starting is difficult ... with very Low Gas, engine is stopping. Long run with full gas, engine is dying as well. So I try to go with „medium“ speed, that normally works ok.

Any other Suggestions what I could do? I am not sure if i should invest in a pretty expensive new carburator for a ten year old and not very reliable outboard engine. Maybe it is better than to buy a new one ...

new needle means the „carburator repair set“? And adjusting the flooding - is that possible for me as a nearly „newbie“? Thanks for every help/ideas

The ultrasonic is a great way to clean the tiny passages in the modern carbs. I do that, and once the organic crud is softened, blow them free with the compressed gas generic carb cleaners.

On all modern carbed motors, if the motor will be off for a week or more, you must have a dry carb. Either idle it until it stalls, or drain it. If there's no gas in there, it won't spoil.

Flooding will occur if the needle/seat does not seal correctly, or if the float is set too high. With the carb bowl disassembled from the body, invert the casting. The float should be about parallel to the casting. If not, a slight bend to the tab that attaches the float should fix that. If it is parallel and still flooding, I would install a new carb kit, such as 3GT871221M, which retails for around $55 USD.

As long as you have good compression, a new carb is not out of the question. And regardless, in the future, always run the carb dry at the end of the day.