John Deere LX188 carb vent overflowing

bertsmobile1 · May 2, 2017

Quick & dirty test is to pinch off the fuel line remover the float bowl, hold the float and see if it cuts off the fuel flow before the float touches the top of the carb body.
In most carbs the top of the float should be parallel to the bottom of the carb when it cuts off the fuel supply

arch252 · May 2, 2017

I sure wish they made those bowls out of some type of clear plastic. That would save me a lot of money and misery.

union farm · Sep 20, 2018

arch252 said:
Sorry to resurrect on old thread. I have an FD590V on a JD345. I cleaned the carb and it is running amd idling great but gas is leaking out of the vent tube on top of the carb while it is running. It will start and stop overflowing while in high idle but pumps out the overflow heavily when reduced to low idle. Is that a needle valve seat / float issue or something else? Not leaking after engine is shutdown, only while running.

Am new here and just wanted to post a possible answer to the overflow tube problem, Have a lx 172 with Kawasaki engine, fuel gushes out the overflow/vent tube while cranking or running. I removed and cleaned carb float and needle seat and reinstalled everything looked good and clean, no change!. However after reading a number of other sites with the same story and problem,wondered even if float looks good and doesn't leak could it be a bitt swollen above tolerance and rubbing on bowl causing no seating of needle. Ethanol could cause minor swelling of float? After inspecting bowl noticed a small casting bump in lower bowl [aluminum bowl] took a small grinder an polished out this casting bump and put back together. Can only surmise the float had swelled just enough to rub against this casting mark which wasn't much but enough to interfere with the float movement. No more leak and runs fine.

bertsmobile1 · Sep 20, 2018

union farm said:
Am new here and just wanted to post a possible answer to the overflow tube problem, Have a lx 172 with Kawasaki engine, fuel gushes out the overflow/vent tube while cranking or running. I removed and cleaned carb float and needle seat and reinstalled everything looked good and clean, no change!. However after reading a number of other sites with the same story and problem,wondered even if float looks good and doesn't leak could it be a bitt swollen above tolerance and rubbing on bowl causing no seating of needle. Ethanol could cause minor swelling of float? After inspecting bowl noticed a small casting bump in lower bowl [aluminum bowl] took a small grinder an polished out this casting bump and put back together. Can only surmise the float had swelled just enough to rub against this casting mark which wasn't much but enough to interfere with the float movement. No more leak and runs fine.

:welcome: :thumbsup:

Auzivision · Aug 19, 2019

This is a great thread!

I am new here as well and have been researching this topic after my John Deere LX188 caught fire.

I've traced the source of fuel to the carburetor vent line pouring fule directly onto the muffler.

Both the fuel pump and carb are new so I'm not sure which to attack first?

Either the pump is creating too much pressure or the carb float/needle/seat isn't stopping the flow properly.

I think I will star with the float using a makeshift gravity feed to replicate fuel pump. Does anyone have a good idea of how much elevation would generate the approximate fuel pressure of the pump?

bertsmobile1 · Aug 19, 2019

A foot or two will be fine.
Compressed air turned down low will also work a treat.
An impulse pump will run at around 7 psi & a mechanical pump should be around the same but some can get to 10 psi.

If you have a fuel line that is falling apart it can very quickly foul the float valve needle.
And a new carb is no guarantee a good carb.
There is a lot of defective parts being sold cheap on the web.

Hitechluddite · Aug 20, 2019

Everybody is looking at the seats but has a float adjustment been made?

As far as finding a carb.

https://www.ebay.com/sch/i.html?_fr....XLX188+c.TRS0&_nkw=lx188+carburetor&_sacat=0

I'll admit ebay is somewhat of a crap shoot on these things, I've ordered 4 carbs for 4 different small engines and one needed mods and worked OK. One didn't work for crap and two were bolt on and perfect. For $20 it's something to consider...

bertsmobile1 · Aug 20, 2019

Hitechluddite said:
Everybody is looking at the seats but has a float adjustment been made?

As far as finding a carb.

https://www.ebay.com/sch/i.html?_fr....XLX188+c.TRS0&_nkw=lx188+carburetor&_sacat=0

I'll admit ebay is somewhat of a crap shoot on these things, I've ordered 4 carbs for 4 different small engines and one needed mods and worked OK. One didn't work for crap and two were bolt on and perfect. For $20 it's something to consider...

Most carbs are available through the regular after market parts newtwork.
They are usually only 10% more than the ebay/amazon cheapies and come with a warranty.
It always amazes me why people would play the parts lottery on ebay & amazon.
hen again it amazes me why people donate their money to multi billionairs buying regular lottery tickets , or as my maths professor used to call them "Idiot tax for the mathematically challenged "
We just elected a government on the back of a $10/week tax reduction.
The average spend on all forms of gambling down here is $ 215 /week per tax payer ( casinos excluded )

deckeda · Aug 21, 2019

Hitechluddite said:
Everybody is looking at the seats but has a float adjustment been made? ...

Hey! Somebody used to work with old cars. But, that won't be an option on these floats that don't use a bendable brass arch at the fulcrum. That method thankfully went away a long time ago (uh, I hope.)

Summary:
For gas that flows out "all the time" look at the suggestions related to float swelling (binding against the bowl), float needle worn, and needle seat worn/dirty

For gas that flows after shutoff look at the suggestions related to excess fuel pressure caused by a worn or damaged pump ... especially before you tear into any discontinued Mikuni carb. I have the emotional scars to prove it.

John Deere LX188 carb vent overflowing

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bertsmobile1

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arch252

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union farm

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bertsmobile1

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Auzivision

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bertsmobile1

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Hitechluddite

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bertsmobile1

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deckeda

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