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Carburetor Flooding

M

Mnethercutt

Member
I have a Marvel Schebler TSX-809 carburetor that is BADLY flooding. I have taken the carburetor apart multiple times, installed a basic kit with new gaskets, and tried various adjustments to no avail. If I crank the tractor and stop cranking, lots of gas pours out the air intake. If I let the carb sit with the gas line open for about 20 mins, gas soaks out between the 2 halves of the carb, particularly badly on the end by the air intake. When I'm able to get it to start (which is a challenge in itself) I have to constantly play with the choke to get it to stay running and it only seems to run on at most 3 cylinders. I'll put a list of things I've tried below but I'm at wits end and am about ready to just send the carburetor off somewhere to get rebuilt. I'm a college student so there's normally a few weeks between weekends when I can get home and work on it, so I'm probably forgetting some stuff that I've done to it. Any new ideas would be appreciated. This is on a john deere 1010.

Here's what I can remember doing:
-Taken carb completely apart and soaked (multiple times)
-Replaced gaskets and installed a new needle, needle seat, and float
-Adjusted float per the instruction manual and tractor service manual
-Swapped out the upper half of the carburetor with another one I had in case of a crack
-Replaced load adjustment needle
 

Forgot to add, this started out of the blue one day. Backed the tractor into the shed, drove forward to straighten up, and when I shifted into reverse to back up again it started blowing a ton of smoke out the exhaust and running rough. Smoke burned my eyes and nose.
 
You either have some rust/dirt in the needle seat area or the float is bad. If you can shake the float and it sounds like it rattle it is bad. Also if the float has a dent in it, it is bad. If you put a kit in it and the new needle is a rubber tipped one you need to put a set in the tip by dropping it in the seat and tapping on it a few time. You then should be able to look at the tip and see a ring set into the tip. Or you do not have the needle seat tight enough and al all of those can cause that problem
 
Everything Old said...

An easy test, before reassembling the bowl to the upper housing, turn the upper housing upside down. With the weight of the float resting on the needle, suck on the fuel inlet fitting, put your tounge over the hole. You should be able to feel it hold vacuum. If it won't hold vacuum, there is still something wrong, a leak somewhere.

The fuel must be clean and the sediment screen in place. I discourage inline filters as they can be too restrictive. If the tank is contaminated with dirt or flaking rust, it will continue to have problems.
 
Plain and simple. The needle is not seating tight. You need to figure out why. Is the needle and seat not mating completely? I usually tap, tap, tap on the needle when installing
the seat and then spin the needle a little and tap, tap, tap again. Repeat, repeat. Is the float tab/spring not pushing the needle against seat tight enough? Stretch the spring or
bend the float tab a bit so it puts more pressure on the needle.
 

Thanks for all the tips--I'll give them a try. I did do the tapping thing when I installed the new needle, and there is a gasket between the seat and the carb body. I'll take it apart again and hope for the best. Maybe the 5th time aparts the charm...
 

I am not saying that this is your main problem, but it will help if you accept that it is normal for a considerable amount of gas to run out of the carb throat when you stop cranking and it has not started. This happens because with the choke closed the suction is very strong so a lot of gas is drawn into the air stream and up into the manifold and hopefully into the cylinders. When you stop cranking the gas that is in the manifold will not defy gravity, it will run down and out. The engine is not flooded unless the spark plugs are dripping gas.
 

Ok, I'm more than willing to accept that. Let's assume that its not flooding. What could cause the symptoms I'm seeing:

-Excessive smoke
-Smell of unburnt fuel
-Only running on 2-3 cylinders
-Very difficult to start and only runs w/ half choke and me playing w/ choke

I have a bright blue spark that will jump an inch gap.
 
Things that can/will cause the problems you have is air cleaner needs to be serviced but since you say you have to mess with the choke to keep it running that means the carb is running lean not rich.

Bad spark plugs or ones that are not hot enough could be the problem even low compression.

So tell use what your working on that helps us help you
 
(quoted from post at 06:55:06 04/23/19)
Ok, I'm more than willing to accept that. Let's assume that its not flooding. What could cause the symptoms I'm seeing:

-Excessive smoke
-Smell of unburnt fuel
-Only running on 2-3 cylinders
-Very difficult to start and only runs w/ half choke and me playing w/ choke

I have a bright blue spark that will jump an inch gap.
Click to expand...

Well, you haven't yet told how the plugs look. That is a very early on check for me. I am leaning towards an intermittent spark situation where you are getting excessive gas building up in 1 or two or three cylinders between the times that the plugs actually fire. Your good spark needs to be verified inside the cylinders.
 

I'll check the plugs when I'm home again, but I installed a brand new set of autolite plugs from tractor supply about a year ago...
 
One thing which has not been mentioned is the float could be dragging on the carburetor bowl. That won't just start like your problem did BUT if it had been apart and was bent and dragging when you put it back together it might run fine until the bowl is empty and the float falls and hangs up again, then it can't shut the valve.

Dripping out the carburetor drain hole will not also cause fuel to come out of the the gasket joint between the upper and lower. That can only come from too much gas coming through the needle valve.

Playing with the choke to get it to run means it's lean so the fuel jet is plugged. I suspect you have rust in the fuel tank. Contrary to other advice given here, I put inline fuel filters on all my gravity fed tractors and never have a problem with them. They do keep specks of dirt and rust from plugging the needle valve. You may have enough rust in your system that the needle keeps getting plugged by more rust after you clean it. That is also something which could occur after sitting for a while. I have been very successful installing an inline fuel filter, cleaning very well from filter to carburetor, and using the tractor. The sediment bowl pretty much catches all the visible dirt, the filter catches the little stuff that will make the needle leak. I generally don't have to ever change the inline filter, I keep the sediment bowl clean, and after the tractor is used the vibration and fuel sloshing cleans the tank.

My actual experience on a couple dozen old tractors.
 

So to reply to the last 2, I did do a compression test recently because I was concerned about valve issues. I got between 135 and 145 on all the cylinders (that is, some were in the 130's, some in the 140's, and I think best was 145), but I'm going off memory here.

I would sure hope that the float isn't bent cause I just put that new one in, but worth a look. I'd agree on the rust issue....but it just so happens that I re-lined the gas tank right before this as I was rebuilding the engine. Certainly could still be a problem, but I hope not.
 
(quoted from post at 05:06:09 04/24/19)
So to reply to the last 2, I did do a compression test recently because I was concerned about valve issues. I got between 135 and 145 on all the cylinders (that is, some were in the 130's, some in the 140's, and I think best was 145), but I'm going off memory here.

I would sure hope that the float isn't bent cause I just put that new one in, but worth a look. I'd agree on the rust issue....but it just so happens that I re-lined the gas tank right before this as I was rebuilding the engine. Certainly could still be a problem, but I hope not.
Click to expand...

It is sounding more like intermittent ignition to me.
 
(quoted from post at 05:48:17 04/24/19)
(quoted from post at 05:06:09 04/24/19)
So to reply to the last 2, I did do a compression test recently because I was concerned about valve issues. I got between 135 and 145 on all the cylinders (that is, some were in the 130's, some in the 140's, and I think best was 145), but I'm going off memory here.

I would sure hope that the float isn't bent cause I just put that new one in, but worth a look. I'd agree on the rust issue....but it just so happens that I re-lined the gas tank right before this as I was rebuilding the engine. Certainly could still be a problem, but I hope not.
Click to expand...

It is sounding more like intermittent ignition to me.
Click to expand...

Intermittent ignition just never makes gas run out the carburetor gasket. Gas has to be coming through or bypassing the float valve. I agree it has more problems, however, either ignition or crud in the fuel jet.
 

So is the ignition a spark plug issue, or a coil or condenser issue?

Or should I just replace something and see if it fixes it
 
You have actual fuel running out of the carb inlet, and you are worried about spark?

Uh - no. There is a problem with the needle seating into the base seat and shutting off flow from the tank.

Old gave you all you need to know. My steps are similar.

1. Remove carb from tractor.
2. Turn upside down.
3. Blow hard into the fuel inlet.(you can't generate enough air pressure to lift the float needle off the seat).
4. If you have ANY air flow from blowing in it, the float is not closing the needle on the seat!

The little tab that holds the needle to the float pivot may be mis-adjusted. If so, the float will be at the top of its articulation, and the needle will not be closing against the seat. There is a spec for the distance from the top of the float, to the upper base of the carb. Measure this when the carb is upside down, and if it is wrong, set the tab correctly.

This is a Zenith carb, but the process is the same. You need the spec for the distance from the float to the flange.

https://www.bing.com/videos/search?q=setting+float+level+in+tractor+carb&&view=detail&mid=5C17C1088DC955BB1E685C17C1088DC955BB1E68&&FORM=VRDGAR
 
(quoted from post at 09:35:59 04/24/19) You have actual fuel running out of the carb inlet, and you are worried about spark?

Uh - no. There is a problem with the needle seating into the base seat and shutting off flow from the tank.

Old gave you all you need to know. My steps are similar.

1. Remove carb from tractor.
2. Turn upside down.
3. Blow hard into the fuel inlet.(you can't generate enough air pressure to lift the float needle off the seat).
4. If you have ANY air flow from blowing in it, the float is not closing the needle on the seat!

The little tab that holds the needle to the float pivot may be mis-adjusted. If so, the float will be at the top of its articulation, and the needle will not be closing against the seat. There is a spec for the distance from the top of the float, to the upper base of the carb. Measure this when the carb is upside down, and if it is wrong, set the tab correctly.

This is a Zenith carb, but the process is the same. You need the spec for the distance from the float to the flange.

https://www.bing.com/videos/search?q=setting+float+level+in+tractor+carb&&view=detail&mid=5C17C1088DC955BB1E685C17C1088DC955BB1E68&&FORM=VRDGAR
Click to expand...


Doc, Uh - No. Try this: remove the rubber air intake connector from your carburetor if you have an old tractor with an updraft carburetor around. Then crank it with the key off or pull the coil wire off, depending on what tractor you have, then crank it for at least eight seconds. You should see then what is happening. This is a very common error in troubleshooting.
 
So I know this is an old topic but I ve finally got home to work on this. To start, I tried the vacuum test where I sucked in and put my tongue on the fuel intake to create a vacuum....and it held. So it seems that the needle does seal, at least upside down.

I have double checked the float spacing and the tab by the flange and it appears correct. I m wondering what I can check next. I m attaching some pictures of the top half of the carb. Let me know what else I can provide.
 
mvphoto36586.jpg


mvphoto36588.jpg
 

Well, you haven't yet told how the plugs look. That is a very early on check for me. I am leaning towards an intermittent spark situation where you are getting excessive gas building up in 1 or two or three cylinders between the times that the plugs actually fire. Your good spark needs to be verified inside the cylinders.
 
(quoted from post at 03:31:28 05/25/19)
Well, you haven't yet told how the plugs look. That is a very early on check for me. I am leaning towards an intermittent spark situation where you are getting excessive gas building up in 1 or two or three cylinders between the times that the plugs actually fire. Your good spark needs to be verified inside the cylinders.
Click to expand...

How do I verify it inside the cylinder?
 
(quoted from post at 04:14:16 05/25/19)
(quoted from post at 03:31:28 05/25/19)
Well, you haven't yet told how the plugs look. That is a very early on check for me. I am leaning towards an intermittent spark situation where you are getting excessive gas building up in 1 or two or three cylinders between the times that the plugs actually fire. Your good spark needs to be verified inside the cylinders.
Click to expand...

How do I verify it inside the cylinder?
Click to expand...

by how the plugs look. Do you know what to look for? reading spark plugs can tell you a lot.
 
(quoted from post at 04:15:46 05/25/19)
(quoted from post at 04:14:16 05/25/19)
(quoted from post at 03:31:28 05/25/19)
Well, you haven't yet told how the plugs look. That is a very early on check for me. I am leaning towards an intermittent spark situation where you are getting excessive gas building up in 1 or two or three cylinders between the times that the plugs actually fire. Your good spark needs to be verified inside the cylinders.
Click to expand...

How do I verify it inside the cylinder?
Click to expand...

by how the plugs look. Do you know what to look for? reading spark plugs can tell you a lot.
Click to expand...

I m gonna defer to the experts on here ;). Let me know if you need more or better pictures.

There s 6 plugs in the photo cause I d grabbed two older plugs I had and had been swapping them around trying to see if it made a difference.

mvphoto36651.jpg




mvphoto36652.jpg
 
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