Tohatsu 3.5 outboard fuel problem

[CAPTAIN FANTASTIC]

I started my Tohatsu 3.5 (four stroke) on the second pull, last time I used it was 12 months ago. However, while is running, fuel pours out from a pipe that is connected to the carburetor. You can see from the picture the cooling water pipe with water flowing and another pipe with petrol coming out.

I don't have the manual with me. I was going to put the engine on the inflatable dinghy and go in the water but I will give it a miss because the waves are pretty high (straits between Evia and Agoii Apostoloi, Attiki) and I need to sort out the engine fuel problem. I may have to remove and to clean the carburetor but before I do this, does anyone had a similar problem?

 

[RichardS]

It's either the carb drain from the bottom of the carb which has come loose and just needs to be nipped up with a screwdriver, or the needle valve is sticking and the float chamber is overfilling. However, as the engine is still running properly, I suspect that it's the drain. Did you unscrew it at the end of last season to drain the carb? I always do as it's best practice but maybe you forgot to nip it up afterwards.

Richard

 

[CAPTAIN FANTASTIC]

Thanks for the reply; initially I thought it was the carburator drain screw but the screw is tight. The fuel runs out from the pipe which is conhected on the top of the carburator. As you are suggesting, the float needle must be sticking. It appears that I need to remove and clean the carburetor.

 

[RichardS]

Thanks for the reply; initially I thought it was the carburator drain screw but the screw is tight. The fuel runs out from the pipe which is conhected on the top of the carburator. As you are suggesting, the float needle must be sticking. It appears that I need to remove and clean the carburetor.

If it's from the top then it's definitely the needle valve. Probably a piece of dirt stuck in the valve seat or on the needle point or the needle just sticking or it could be worn and need a new needle and/or seat. However, as it's running that quickly, I doubt that it will be wear so just a clean up should sort it.

Richard

 

[VicS]

Thanks for the reply; initially I thought it was the carburator drain screw but the screw is tight. The fuel runs out from the pipe which is conhected on the top of the carburator. As you are suggesting, the float needle must be sticking. It appears that I need to remove and clean the carburetor.

Its a vent pipe similar to #32 in this diagram ( which may not be exactly the same as your carb because you have not given its age so picked an example at random)

https://cdn.boats.net/MTA/d/0/MjEwMzc2-07bc8c92.png

Its flooding almost certainly, because as richard says the float needle valve is not closing properly. . Dirt on the seat or because the needle or float is stuck. A gentle tap may free it but most likely you will have to get in there but will never know exactly what the trouble was

 

[CAPTAIN FANTASTIC]

Great, thanks

 

[Spyro]

Had the same problem a couple of times when the carb float bowl gets gunged up causing the float to stick. The carb bowl may be able to be removed without dismantling the carb from the engine.