Carburetor Still Leaking...A Lot

[8N_John]

After I turn off my 8N (and before I turn off the fuel), gas is leaking out of the small hole in the bottom of my carburetor at a good pace...a small continuous stream of gas (a lot more than dripping). I recently bought a carb kit because of this problem and replaced many parts and gaskets (but not the float).

The float looked OK, but I don't know what a bad float looks like. Any advice on what the problem could be?

 

[jinman]

John, a bad float is normally one of two things. The float itself may have a pinhole in it and actually sink instead of float. You can check this by putting it into a small container filled with gasoline and watch to see if it sinks. The other problem is the float out of adjustment. The arm from the float to the hinge may become bent so much that the float does not push up on the needle valve and shut off fuel. You can correct this by slightly bending the float hinge lever. Didn't your kit come with instructions for assembly and adjustment?

Take the carburetor off the tractor and remove the float bowl. Turn the carburetor upside-down and measure the distance between the float bulbs and the body of the carburetor. It should be 1/4" or 0.25". Or, if a pencil is exactly 1/4" thick, you should be able to slide it under the bulbs from side-to-side. If it's greater than .30" , it's out of tolerance.

The most common float problem is trash in the float valve. While you have the float chamber apart, clean out any trash and make sure the needle valve will shut off the fuel. If you have to, put the fuel line to the carb and see if the fuel stops flowing while you lightly push up on the float bulb. I'm just sure you will find trash, a damaged float valve, or a damaged float valve seat. Most often it's just trash. Good luck! /forums/images/graemlins/smile.gif

 

[Soundguy]

I've found that the 'chuck' side of a 1/4" drillbit is an excelent float setting tool.

Also.. sometimes those neophrene/viton tipped needles arn't good about seating.

Soundguy

 

[jinman]

</font><font color="blue" class="small">( Also.. sometimes those neophrene/viton tipped needles arn't good about seating )</font>

Absolutely, Chris. I just think 8N-John has got to find out why his fuel isn't shutting off. He knows the symptom (leaking) but doesn't know if it's the float or the needle. If he can figure out which one is causing his problem, he can fix it. It doesn't take much trash to make that valve leak and a pitted seat will cause leakage too. If I were a betting man, I'd agree with you that the problem is most likely the needle valve rather than the float. However, if the lever is bent, the float could be binding on the side of the bowl. The only way to find out is to take it apart and check it. It's not that hard of a job and it's a really simple device. /forums/images/graemlins/smile.gif

 

[Paddy]

SoundGuy,

Agree, I just put a new set of carb parts on my Harrey Ferg TO-20, Same carb. Still leaks out if I don't shut it off at the tank. I will hook up the fuel line with the bowl off and see if it stops when I push the float up. The carb has to be removed to drop the bowl, screws come from the top

 

[8N_John]

Thanks for the info. I did replace many parts, but not sure if I replaced the needle. Is that the piece that butts up against the float and is imbedded in a cylindrical type piece? Sorry, I'm a beginner. If that's what it is, I have the part but I couldn't figure out how to get it out. Looks like you use a flathead screw driver but the needle sticks out slightly past the portion that you screw?

I'll also measure the float spacing.

 

[jinman]

John, I'm attaching a combined scan image of the float adjustment and the carburetor parts exploded view. The red arrow points at the float needle valve in both drawings. Notice the float valve has a seat and a seat gasket. Did your rebuild kit come with all these parts? A full kit should include them I think.

Anyhow, the green arrow points at a hinge pin that is easily removed so you can get to the float needle. The blue arrow points to the gage used to set the float height. Look at all these parts and make sure your carburetor is not missing anything. There is a spring right below the float that is shown on the parts page. It's easy to lose that spring.

When you work on the float, it's easiest assemble if you take the carburetor off and turn it upside down. Some folks who are experienced can work on it on the tractor, but I'd take it off and sit it in a plastic dishpan or other container while I disassembled it so if a tiny part falls off, you won't have to try to look for it on the floor.

 

[Soundguy]

Nice... I can't think of anything to add to that post.

8nJohn.. Jinmans done all the book work for ya, so go ahead and grab your carb dip pan and hit it one more time.

Soundguy

 

[8N_John]

Thanks! Exactly what I was looking for. I still have a problem....I can't figure out how to get my needle out. It is lodged in the seat (my carb kit came with new needle and seat). Thought about taking out the seat assembly but I can't get a screwdriver in the notch because the needle is sticking out past the notch.

What's the proper way to remove the needle?

 

[jinman]

John, it sounds like your carb has the wrong needle/seat combination or something fishy is up. That needle normally falls out of the seat. Is it loose, but sticks when you try to pull it out? I think I'd grab a pair of pliers and pull it like a tooth. After all, you do have a new set to replace it and it sure ain't working right now. That's the best advice I can give without seeing it. /forums/images/graemlins/confused.gif

Do you know anybody with a digital camera?