Gas leaking from carb top vent tube

[arch252]

And Bert, it's a FD501V and it is the carb pictured above.

 

[bertsmobile1]

Thanks Arch,
Not an engine I am familiar with
slip the float bowl off and while holding the float up lightly with you finger, crank the engine to see if the carb can cut the fuel supply off before the float touches the carb.
If you got the carb from AmmoZone or Evilpay then better than average chance it is a defective one bought as scrap from the factory then resold as good to cheapskates
When removed & tipped upside down the carb should hold 7 to 10 psi with just the weight of the float.
Fuel pump carbs usually have a slightly longer needle than identical looking gravity feed carbs
I get 1 or 2 a month through the gate wanting me to find the "mystery" fault they can not even after they have replaced everything
And I find the new carb is defective
I have even had more than one person supply me with multiple replacements for the defective carb that were all defective because were sure my $ 60 carb was just one of their $ 10 carbs with a $ 50 mark up. ( they get charged actual hours so by the time they find a good one they have racked up a hundred or more in labour )

 

[StarTech]

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.

You use a fuel pressure gauge. Max output pressure should be under 10 psi as to not to over pressurize the fuel line at the carburetor.

And as Bert said even new carbs can be defective. I had one OEM carburetor this year that failed to hold off the fuel pressure on a gravity fed system. The distributor replaced it free of charge under warranty. With after market they may be supplying a gravity flow version and not a pump fed version.

BTW the Kawasaki OEM fuel here lists for $81.50. And JD brick and mortar shops asking $185.40. So that $15 pump is an aftermarket clone pump.

This one is the online priced JD pump.

 

[arch252]

Thanks Bert, I'll check that as you described. I just find it extremely unlikely that both the OEM carb AND the replacement carb would both fail in exactly the same way. That would be quite the coincidence and I have a hard time accepting coincindences.

 

[Rivets]

The basic FD501V engine has at least 4 different carb which can be use, depending on the Spec number. Could very easily have the wrong carb as they all look the same.

 

[StarTech]

Thanks Bert, I'll check that as you described. I just find it extremely unlikely that both the OEM carb AND the replacement carb would both fail in exactly the same way. That would be quite the coincidence and I have a hard time accepting coincindences.

Believe it. It is possible as I had it just happen about two months ago here with a MTD P90 engine. And both carburetors were OEM one at that.

 

[slomo]

OP seems to have a good answer book.

1.Used OEM carb leaking fuel, I get it. Remedy the needle and seat.
2.New "UNTESTED" Chinese carb, definitely understand slash expected it. All carbs should be pressure tested.
3.Going by the most likely cause is getting you nowhere.

Story went from a leaky carb to a fuel pump issue. Still not cutting grass.

 

[Deleted member 97405]

I have encountered this exact issue numerous times over the years. What happens, due to age, the fuel pump begins to deteriorate internally, even though it still works! Since the pump is after the fuel filter, the particles go straight to the carb and block the inlet needle open. You can clean as best as you want, but you'll never get all the particles, and more will come as the pump continues to deteriorate. You will have to replace the fuel line from the tank all the way to the carb as well as install a new fuel pump. Take your new carb off and remove the needle and float. Remove any debris from the bowl, needle, and inlet tube (the part your fuel line connects to) This is the ONLY way to completely rid the system of the problem. Blame ethanol gas. It dries out the older fuel system components over time. Once updated, you should be ok with ethanol fuel again unless you use all Chinese parts. Then the issue will come back eventually because they use inferior rubber parts, which ethanol will attack. Ethanol will also attack plastic parts, i.e. floats, in Chinese carbs as well. Just FYI. Ask my neighbor. Fuel ate right through his float in 6 months. Fix it right if you plan on keeping it. It will be expensive, but it beats spending $4000 or more for a new tractor. For comparison, the current X350 or X380 is the replacement for your tractor if you want to get some prices. No point in scrapping it, just fix it right, and let Amazon keep their Chinese junk. You should be able to find a Kawasaki carb and fuel pump versus spending Deere's stupid high prices. I have done this repair more than I can count on these machines. Ethanol is the problem, politicians enact it, we pay for it. But I digress....Hope this helps!

 

[arch252]

I have encountered this exact issue numerous times over the years. What happens, due to age, the fuel pump begins to deteriorate internally, even though it still works! Since the pump is after the fuel filter, the particles go straight to the carb and block the inlet needle open. You can clean as best as you want, but you'll never get all the particles, and more will come as the pump continues to deteriorate. You will have to replace the fuel line from the tank all the way to the carb as well as install a new fuel pump. Take your new carb off and remove the needle and float. Remove any debris from the bowl, needle, and inlet tube (the part your fuel line connects to) This is the ONLY way to completely rid the system of the problem. Blame ethanol gas. It dries out the older fuel system components over time. Once updated, you should be ok with ethanol fuel again unless you use all Chinese parts. Then the issue will come back eventually because they use inferior rubber parts, which ethanol will attack. Ethanol will also attack plastic parts, i.e. floats, in Chinese carbs as well. Just FYI. Ask my neighbor. Fuel ate right through his float in 6 months. Fix it right if you plan on keeping it. It will be expensive, but it beats spending $4000 or more for a new tractor. For comparison, the current X350 or X380 is the replacement for your tractor if you want to get some prices. No point in scrapping it, just fix it right, and let Amazon keep their Chinese junk. You should be able to find a Kawasaki carb and fuel pump versus spending Deere's stupid high prices. I have done this repair more than I can count on these machines. Ethanol is the problem, politicians enact it, we pay for it. But I digress....Hope this helps!

 

[arch252]

I replaced the fuel pump, no change. I dropped the bowl on the carb, bowl was clean. Checked the float, held it level with my finger and it cut off the fuel supply. I went ahead and removed the float and needle to remove any possible debris. Put it back together. Still pumping A LOT of fuel out of the top vent while it's running, worse than before.

So to summarize everything so far: mower was running rough, had to keep it choked to keep it running. I noticed some fuel coming from the OEM carb top vent tube. I screwed up the jet trying to remove it while cleaning the carb. I replaced the carb with a new aftermarket. Same thing, leaking gas from the top vent tube while running. I replaced the OEM fuel pump with a new aftermarket, no change, still pumping fuel, even stronger now, out of the vent tube.