Carb Pouring Gas

Folks I'll tell you right up front that I have posted this same question on another forum, so I apologize in advance for the redundancy, but I need more help. As the subject says, the Marvel Schebler TSX 765 carb on my tractor is pouring gas out of the air intake. I have taken it apart and soaked and cleaned it as good as I could get it, and then rebuild the carb with one of the comprehensive kits that are over priced. Just as soon as I turn on the gas, the carb will fill up and start pouring out of the air intake. I've now removed and replaced it about 20 times making adjustments and checking the things that some people have suggested. This is what I have done so far: I've made sure the float is good and air tight. I've double and triple checked the float level. I've checked the float drop and made sure it is not touching the sides of the carb. I took the needle and seat back out and I put a small bead of anaerobic sealer around the flange of the seat and reinstalled it. I waited 24 hours for it to cure and then replaced the carb and hooked everything back up. Turned on the gas and within two or three seconds, it started pouring gas out of the air intake.
I don't know what else to do. Has anyone ever dealt with something like this? Any suggestions? Thanks for your help.
 
Pull the carb off and then pull the float bowl off of it and put what is left back on and hook it up to the gas line. Hold the float up with your fingers and turn on the gas and watch and see what is going on. Seen more then one with a hair line crack cause that or the needle is not seating like it should and cause that
 
I had this happen to me a while back.
After much hair pulling I took someones suggestion and rechecked the needle seat for tightness. Made a tool that I could put some "stuff" when tightening.
I was able to get just a minute amount of movement.
Problem solved.
 
Fellas is the needle and seat the only place that gas can get by to flood the carb? Is there any other orifice or something that gas can get by? Anything else that I should be looking at? I appreciate your comments, but I've tried all that you have mentioned so far, but it's still doing it. I'll tell you what, I'm getting to be an expert at pulling that carb and stripping it down and putting it back together again. I just hope I haven't put something back where it wasn't suppose to be. They seem to be pretty simple and pretty much fool proof, but I know I can screw something up if I try.
 
So your saying you have installed the top half of the carb and held the float up and it stops gas flow that way?? If you have done that then the float needs to be set a tad bit lower so it comes up fast and harder. Yes unless you have a cracked carb that is the only place comes into the carb
 
Bloody gassers.
There is always something on them that's leaking
or needs tweaking.
Someday you oughta think about a diesel.
They stink and they're noisy.
But they Always run.
 
Seen many a diesel that would not run due to some odd problems so can not agree with you. Friend has a 4600 that would die after a couple minutes due to the fuel shut off valve do dad missing the stand pipe. I replaced it and it ran fine. It is a diesel by the way
 
Even though it's a new needle and seat don't trust it. Put a new Tisco one in the 740 I got a few weeks ago and it worked about 5 mins then poured strait through. Took the carb apart checked everything and still the same. Put the old needle and seat in it's still holding fine. I'm a dealer for Tisco, A&I, and Atlantic and its a toss up sometimes if the new parts are going to work.
 
No, I haven't done that yet old. Mosquitos were about to eat me up so I had to quit and come inside. That's the first thing on my list tomorrow.
 
I put the old needle and seat back in mine today also and it does the same thing, no difference.
This tractor was running find until just the other day when I went to crank it and the gas came pouring out. It's definitely a head scratcher.
 
Shoot in my area we have had so much rain mosquoto hit you before you get a foot out the door LOL
 
you said that you have made sure the float isn't touching the bowl. good. check it again. The tiniest burr in the bowl can grab it when it's back on the tractor.
Check the float pin to make sure it isn't too sloppy in the float.
If it is, the float can tip slightly when using the tractor.
On the bench when you are done, tip the carb upside down and blow gently in the inlet with a hose and your mouth.
right side up, upside down.....ok it works.

and as always...clean, clean fuel supply. One tiny speck of debris will hold that needle open and undo all your hard work.
screens, filters, tank............don't forget the inside of the fuel line.
 
(quoted from post at 08:25:19 07/09/15) you said that you have made sure the float isn't touching the bowl. good. check it again. The tiniest burr in the bowl can grab it when it's back on the tractor.
Check the float pin to make sure it isn't too sloppy in the float.
If it is, the float can tip slightly when using the tractor.
On the bench when you are done, tip the carb upside down and blow gently in the inlet with a hose and your mouth.
right side up, upside down.....ok it works.

and as always...clean, clean fuel supply. One tiny speck of debris will hold that needle open and undo all your hard work.
screens, filters, tank............don't forget the inside of the fuel line.
 

""On the bench when you are done, tip the carb upside down and blow gently in the inlet with a hose and your mouth.
right side up, upside down.....ok it works.""


I always do that to check it before it goes back on.. It will show the needle sealing correctly and also the float moving and not hanging up. So it gets done serveral times. Only does not test the float for leaks though.
 
As part of your rebuild, did you replace the tiny gasket on the main nozzle? If not, you can do it without removing the carb from the tractor. With the fuel shut off, remove the power adjusting needle unit. Shine a light up in that hole and you will see a slot on the bottom of the nozzle. Using a small screwdriver turn it CCW and it should pop loose (may be in there tight). It is best to use a carburetor screw driver for this (and for installing needle valve seat) because they are ground flat so as not to distort the part. Anyway, when you get the nozzle out, there is a small gasket halfway up. Replace that, reassemble power adjust needle. -Will
 
(quoted from post at 21:08:54 07/09/15) As part of your rebuild, did you replace the tiny gasket on the main nozzle? If not, you can do it without removing the carb from the tractor. With the fuel shut off, remove the power adjusting needle unit. Shine a light up in that hole and you will see a slot on the bottom of the nozzle. Using a small screwdriver turn it CCW and it should pop loose (may be in there tight). It is best to use a carburetor screw driver for this (and for installing needle valve seat) because they are ground flat so as not to distort the part. Anyway, when you get the nozzle out, there is a small gasket halfway up. Replace that, reassemble power adjust needle. -Will
ood call, Will.
 
Thanks, JMOR. I had the same experience as this fellow and went through the same repairs and when I did what I described above, it stopped
leaking and has been fine since. In my case, the crankcase was contaminated with fuel from the tractor sitting (and from the fuel shutoff
that didn't work). Amazing that engine failure could have resulted from a defect in such a tiny part...Will
 
Well I took it back off again today to make sure I hadn't left a gasket off (I didn't). I put just the upper half back on and turned on the gas while holding the float up. It cut the flow of gas right off.
I then took it back off and started looking at the float real close and it looked like the bottom part of the float was flared out a little to much and dragging the side of the float bowl. I hadn't noticed this before even though I checked to make sure there was no interference before. I guess I didn't check close enough. I carefully bent the bottom edge of the float arms inward a little bit and it gave the float more room on the sides of the float bow. Put it back together and turned on the gas and waited for it to start overflowing. It didn't so I cranked on it a few times and it fired up. Started spitting and backfiring at first, but eventually cleared up. I think there may have been gas in the cylinders causing this, but I'm not sure.
I just wanted to say thank you to ALL of you fellas for coming to my rescue and helping me get this old tractor up and running again. Thanks.
 

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