2011 20 hp Tohatsu carb leaks

[Mindenboater]

I have a 2011 4 stroke 2011 Tohatsu. Carb was leaking fuel from the lower overflow pipes into the water. Engine does run but will cut out after a while - basically sounds like it is flooding. I cleaned the carb expecting it to be an issue with the float or needle. Still leaked. I then poured some fuel into the carb bowl, just covering the bottom of the bowl and it leaked out.

Any thoughts on what could be wrong and what parts I would need? Could it be the plunger?

Thanks
KFG

 

[pvanv]

Year is irrelevant. What is your actual model? You are likely flooding. Probably due to a bad needle/seat/float. What method did you use to clean the carb? When you poured fuel into the bowl, was it off... on the bench? Where did it leak? Yes, the plunger is its own seal, and if damaged, could leak. There are also 3 o-rings in that assembly; two of them could allow a leak to the air. The drain screw is in the bottom of the 20C plunger cap. Is that installed with the correct gasket washer?

 

[Mindenboater]

Thanks for the response.

It is a MFS20C

Cleaning process was to remove jets and soak everything in carb cleaner for 6 hrs. Clean out bowl and float. Blow all orifices with compressed air.

When I poured fuel into the bowl the bowl was off the carb on my workbench.

Fuel leaked out from the bottom of the bowl through the 'overflow' pipe. ( Not sure what this pipe is actually called). It is not leaking through the drain plug. I did notice that the plunger bellows seemed worn.

 

[pvanv]

There isn't any overflow pipe. If you left the plunger installed while in carb dip, it probably is shot now. Where exactly on the diagram is the leak?

 

[Mindenboater]

This pipe that fuel is leaking from is just behind and slightly above where the diaphragm cover (32) attaches to the bowl

 

[Mindenboater]

Hope you can see this picture. The black pipe in the middle is where the fuel leaks out

http://s1320.photobucket.com/user/Mindenboater/media/IMG_0088_zpssofwey6z.jpg.html?sort=3&o=0

 

[pvanv]

That's a vent hose. If fuel is running out of there, the bowl is over full. If it's leaking Near there, the bowl is cracked, and you will need a new one.

 

[Mindenboater]

Fuel is definitely coming out of this pipe. Not from near it. And it comes out when I put a very little amount of fuel (1/4 inch) in the bottom of the open bowl. is there some type of ball valve at the bottom of the bowl?

 

[pvanv]

The carb bowl is available new.

 

[Mindenboater]

Thanks for your help. I replaced the plunger and it sorted out the problem.

I just noticed that my carb is missing part no 36, the check valve. Very long shot question. Is it possible some models do not come with this part. My fear is that it fell out and is long gone.

 

[pvanv]

If the plunger rubber was bad, it could allow fuel to the air side, yes. You are not supposed to soak the rubber bits in carb dip.
You need the check valve to help the plunger cavity to refill.

3BJ031980M

CHECK VALVE

$11.73

 

[MissionSix1]

I am curious as to was there any other issues you had while replacing the plunger? I believe I am having the exact same issues on my 2014 Tohatsu 20 hp.

 

[GA_Boater]

I am curious as to was there any other issues you had while replacing the plunger? I believe I am having the exact same issues on my 2014 Tohatsu 20 hp.

Pleases start a new thread. The OP was here for a month and never returned.

Closed.