Gas leaking from carb top vent tube

arch252

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I've got a JD LX279 with liquid cooled 2 cylinder Kawasaki. It was running rough, seemed to be missing if I'm running over rough ground. I noticed some gas coming from the top vent tube. I took the carb off to clean it and stripped the main jet trying to remove it. I replaced the carb with a new one and it is also dripping gas from the top vent tube while running. Obviously not a carb issue. Is this an issue with the fuel pump? Attached a photo of the type of fuel pump it uses.
 

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Rivets

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I wouldn’t blame the pump so fast. To me it’s more likely the float needle and seat not shutting off, allowing to much fuel to enter the carb. I would be removing the carb and check to make sure they are working properly.
 

arch252

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I replaced the carb, new carb did the same thing
 

hlw49

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Did you replace the fuel line? Could be the fuel line is deteriorated on the inside and parts of it crumbled out and got between the needle and seat. I always replace the fuel filter and line between the filter and carb when replacing carb.
 

arch252

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The fuel line from the fuel pump to the carb was stiff but not deteriorated, it was less than 3 years old but I went ahead and replaced it as well.

I can't think of any other cause than the fuel pump but don't know what would cause a fuel pump to do that.
 

Rivets

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If fuel is exiting the carb through the vent tube, the float needle is not shutting off fuel to the float bowl. If you purchased a carb off Fleabay it wouldn’t surprise me that it is bad. I have no idea why you would suspect the fuel pump, as it must be working fine if you have excess fuel in the carb.
 

arch252

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The OEM carb was leaking fuel out of the top vent tube. I replaced it with an aftermarket carb that did EXACTLY the same thing. Common sense tells me something else caused both carbs to malfunction in the exact same way. I don't know that it's the fuel pump but I don't know what else it could be, that's why I posted.
 

bertsmobile1

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I am a bit confused here.
You say fuel is leaking from the carburettor vent tube
I don't see a carburettor vent tube listed in the IPL I have here
And they have not been fitted to mower engines since around 2000 when venting to atmosphere became illegal
So can we have the Kawasaki engine details please ?
 

StarTech

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Am128355 (Kawasaki 15003-2653)
Replacement for Kawasaki 4 stroke Carburetor engine Models FD501V-AS03 FD501V-AS05 FD501V-BS02 FD501V-BS03 FD501V-BS05 FD501V-CS02 FD501V-CS05 FD501V-DS05 FD501V-ES05
1662777364506.png

Connect fuel pressure gauge to the output of the fuel pump and report your findings.
 
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arch252

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I don't even know how to measure the fuel pressure so I know I don't have the equipment for it.

I don't typically diagnose by replacing parts but if the fuel pump is the most likely cause I don't mind spending the $15 on a new one. I just needed to know if a fuel pump could fail to cause excessive fuel to be pumped.
 
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