Carbs always leak

Graveyard1984 · Mar 10, 2018

Ive owned several antique tractors
Every one the carb always leaks gas
out of the throat of the carb. Ive rebuilt the carbs and ive had other people rebuild the carbs and they still leak gas. I run non ethanol gas. Ive checked the needle and seats and floats and they still leak.

What am I doing so wrong? How do i correct this problem?
Thanks

Greg1959 · Mar 10, 2018

Graveyard1984- No worries, you are doing fine. That kind of situation is inherent with down draft carbs. It's okay.

That's why the shut-off valve in fuel line was used.

carvel minne farmer · Mar 10, 2018

(quoted from post at 22:17:40 03/10/18) Graveyard1984- No worries, you are doing fine. That kind of situation is inherent with down draft carbs. It's okay.

That's why the shut-off valve in fuel line was used.

ditto what greg said graveyard, another thing I do graveyard is when i'm not going to be using the tractor for a while (month or so) I will shut the fuel off at the valve when I have it parked where I want it and let the engine run the carb dry and quit on it's own then shut the switch off. that way you won't have fuel sitting in and gumming up the carb. todays fuel your buying is crap graveyard and this method will save you a whole bunch of problems and headaches.

Graveyard1984 · Mar 10, 2018

Every time i get off the tractor i always shut the fuel off and let the tractor run till it quits. Even if its just for a few mins.

carvel minne farmer · Mar 10, 2018

(quoted from post at 22:41:07 03/10/18) Every time i get off the tractor i always shut the fuel off and let the tractor run till it quits. Even if its just for a few mins.

graveyard is it still leaking after you shut the fuel off and it quits?

Graveyard1984 · Mar 11, 2018

After the tractor quits the leak stops
also.

But once I turn the gas back on before
i get to the seat gas starts leaking
out of the carb

carvel minne farmer · Mar 11, 2018

(quoted from post at 23:01:33 03/10/18) After the tractor quits the leak stops
also.

But once I turn the gas back on before
i get to the seat gas starts leaking
out of the carb

sounds like float setting?

Moonlite37 · Mar 11, 2018

updraft

gene bender · Mar 11, 2018

some will tap the rubber needle at little when installing I do agree sometimes they can be a problem all 10 0f my As,Bs and Cubs do seal and not leak

rrlund · Mar 11, 2018

Electric inline fuel shutoff. It's hooked to the ignition switch so when I turn it on,it opens and lets the gas flow to the carb. I have them on three tractors.

mdross · Mar 11, 2018

Sounds like the float level is a tad too high. Set right they should not leak out form there at least. Otherwise gasket surfaces need to be renewed.

Traditional Farmer · Mar 11, 2018

I have trouble making those rubber type needle valve leaking and you may be making them worse by running the tractor out of gas every time its lets the rubber dry out and maybe shrink or crack.I save every old metal needle valve I find

AlinArk · Mar 11, 2018

if the leaking is normal in an updraft i must be doing something wrong, as all my updrafts do not leak..... hafta fix that....

D Slater · Mar 11, 2018

That looks like a good size shut off to use. Mind sharing what brand model or type? Thanks

Andy Martin · Mar 11, 2018

(quoted from post at 04:55:48 03/11/18) Sounds like the float level is a tad too high. Set right they should not leak out form there at least. Otherwise gasket surfaces need to be renewed.

I agree except for the gasket surfaces. A dragging float can also cause you fits, and it's not always easy to tell if the float is hanging up. Beating on the carburetor with a Crescent wrench is the common fix for a dragging float but not my preference. The only reason for the bowl gasket is to keep gas from sloshing out when moving. Sitting still it sees no gas.

rrlund · Mar 11, 2018

I'd have to look. I found it among my son's stuff from a nitrous kit in the shop. I found two or three more in boxes out there. I'll check later when I go out. The one on my 500 is one I got off Amazon. It's the same size,but the quality isn't quite there. I had to grind the end off the pin to get it to open far enough. The rubber swelled or something.

Ultradog MN · Mar 11, 2018

"How do i correct this problem?
Thanks"

Sell your gassers and buy a diesel.

Goose · Mar 11, 2018

You don't say what kinds of tractors, but on Farmall H's and M's I've learned to set the float level about 1/8" lower than what the book says.

Probably holds true on other makes.

BarryfromIA · Mar 11, 2018

rrlund I have wanted to ask the model and where you got the shut off. I think your said Amazon some time back.

Dave H (MI) · Mar 11, 2018

I only have one I think that leaks. I learned a couple years back that if I was going to redo a carb, I first evaluated did it leak at the carb. If no, then I changed as little as possible with the float and needle. And the one thing I do for sure is save the old needle. If it ain't broke don't fix it. A lot of us get hung up on the "while you're in there" philosophy and just replace stuff on spec. If I was inside the engine, yes. Inside the carb, no.

DoubleO7 · Mar 11, 2018

Just google or amazon for "12vdc fuel shut off valve".
Make sure it is compatible with your fuel, normally closed and able to stay open for the hours intended. Most mention not to use for 6 to 8 hours at a time or the solenoid will get too hot.

rrlund · Mar 11, 2018

Here's a picture of the ones that are new in the box out there. No brand name on them. They're a little bit longer and not quite as big around as the one on the 77. I'd have to take the screws out of the side cover to get a look at the one that's in the picture,and then there's no guarantee the decal would still be readable.

rrlund · Mar 11, 2018

The one on the 500 came from Amazon,yes. The one on the 1600 is off a New Idea Uni Harvester that I parted out. The one on the 77 is from a Nitrous kit.

the tractor vet · Mar 11, 2018

What a lot of untrained people thhink is a carb leak on a UP DRAFT CARB is not a LEAK persay . It is the fuel that did not make it all the way up into the engine either while starting or during shut down and this is when gravity takes over and it Falls back down and puddles in the throat area of the carb and then drips out the WEEP hole in the bottom of the throat . ALL up drafts do this . ON carbs that are DOWN DRAFTS that WET fuel puddles in the manifold and there fore MOST people do not see this . ON some of the larger updraft bigger tractors one can see bigger puddles or drips hanging off the bottom of the carb . This DRIPPING should stop after a few min . NOW if you have gas / fuel streaming out or you filling the engine and air cleaner THEN you have a carb problem . I have had many gas tractors in my life time and rebuild countless carbs and they all will drip on start up if the engine does not light first try and you let it set . When you have the choke on they do suck a lot of liquid fuel up the pipe and when you either flood the engine and that is exactly what your doing is FLOODING the engine with LIQUID gasoline like i said what is on the way up when you stop cranking falls back down and there can be ALOT of liquid. . Easy way to check is pull the air cleaner hose and see if it is just puddled gas or a running stream coming from the bowl overflow drain . When rebuilding a carb one can BENCH test to see if you have down the job right the first time by simply usen your mouth and BLOW into the inlet , with the carb held as it is mounted blow into the inlet , air should pass thru easy , then turn the carb upside down and blow again if you cant BLOW thru it then the Neddie and seat is doing it's job if you can then you screwed up try again.

da.bees · Mar 11, 2018

I have to agree with those who say if the needle and seat isn't leaking before overhauling,reuse them( I feel the same about ignition parts). If a leaky needle is the only problem to start with or if a new one leaks,I have good luck with lapping it in with 600 grit paste.

Traditional Farmer · Mar 11, 2018

Can always use one of those inline manual cutoffs that you can get for $1 off ebay work like a charm.

Frank 41 · Mar 11, 2018

When you park your tractor, shut off the fuel, and let it die, DRAIN the carb.

504 · Mar 11, 2018

I always shut the fuel off,gas is just too expensive and too hard to carry to waste it. The needle and seats are 99% made in the land of close enough. I always polish the three sides of the needle(out side points)and twist up a wad of 0000 steel wool and polish the inside of the seat. (BTW you can polish aluminum, glass, chrome, almost anything with 0000.)
I do not care what the instructions say, or the neighbors best friends buddy who once was in a dealer ship. I set the float by turning the body upside down and setting the float to be level with the body. Make sure the float moves in the bowl.

caterpillar guy · Mar 11, 2018

Our H does not leak even being hauled. We never shut the fuel off on it. It is used fairly often year round.

Carbs always leak

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