carb leaking

[kully560]

hello again,I need some help , my 1959 i/h cub low boy has a gas leak at the carb choke shaft on both sides, is this rebuildable or do In need a new carb? if there is a kit where is the best place to purchase it? as for the carb I do not want a china nock off from ebay any suggestions thanks

[Bob McCarty]

Is this an IH or Zenith carb?

[Don McCombs]

Under normal circumstances, there should be no raw fuel in the area of the choke shaft and plate. You need to look deeper for the source of your leakage. I would recommend starting with a check of the float adjustment.

[kully560]

to answer Bobs question I do not know who makes the carb but I do know the tractors history and it is all original if that helps. also thanks Don I will look deeper .

[NJ Farmer]

If your carb is leaking at the choke shaft your float is either sunk or float setting is too high. The carb can be rebuilt but it needs to be rebuilt following the service manual to get the correct float setting. When you get it apart shake the float….if it has fluid in it it’s garbage.
If not reset the float height following the service manual.

NJ Farmer

[Eugene]

Leaking out the choke shaft, both sides. That's a lot of fuel in the air cleaner hose.

Drop the air cleaner bowl. Clean and let any fuel evaporate from the air cleaner.

As stated, the problem is with the needle valve, seat gasket, or float.

Suggest doing a bench test for the leak source.

Edit: After you get the carb fix and before starting engine; check the engine oil for fuel smell, remove spark plugs and crank engine over without starting.

[Dale Finch]

Are you sure the fuel is not dripping out the bottom, where there is a drain? It will do that after an unsuccessful start attempt...normal.

[Glen]

Hi,
The IH carburetor is what came on a 1959 LoBoy, and many other years of Cubs.
IH started using the Zenith carb during 1975, and people have put them on other years of Cubs and LoBoys.

Below are pics from TM Tractor.

The 1st pic is an IH carb, they usually have 2 IHs cast into them.

The 2nd pic is the bottom of the IH carb, showing the drain hole for excess gas, if any gets into the air intake. The hole has a filter material in it. If it is plugged with dirt, gas couldn't drip out of it.
Gas is supposed to drip out the hole, if needed.
If the carb is working right, no gas would drip out of it when sitting.
If you try to start the Cub and it doesn't run, gas can drip out the hole then, like Dale said above.

The 3rd pic is a Zenith carb.
The Zenith carb uses a different float level than an IH carb.

You have to take the carb apart to set the float level.
When removing the top from the IH carb, pull the 2 halves straight apart for 3 or 4 inches.
There is a small idle tube that is attached to the top half, and sticks down into the bottom half.
If you twist the 2 halves apart, you can break the idle tube.

TM Tractor has individual carb parts.

[kully560]

thanks for all the help , it was a clog screen like Glen suggested , all good now!!

[Stanton]

thanks for all the help , it was a clog screen like Glen suggested , all good now!!

Was the bottom drain filler material clogged, preventing gas from draining out the bottom? I'm having a hard time believing your carb woes are over if you have enough gas inside the air intake compartment to cause gas to drip, then the float still needs to be addressed.

Air intake compartment.

carb.JPG (29.13 KiB) Viewed 388 times

If you ever need a rebuilt kit, then I'd recommend McDonald Carb, found here: https://www.mcdonaldcarb.com/category_s/359.htm

[kully560]

the screen was clog , I removed the air filter rubber hose and sprayed carb cleaner into the screen and when the motor runs now I hear a little whistle like air passing through the screen . I do not think it is the float as the carb is original and the tractor has never been mess with .could be maybe I did not have the fuel shut off valve closed tight enough and gas drip out of the choke shaft instead of the screen . but all looks good so far , thanks

[Rick Spivey]

If you are talking about the screen wire in the air cleaner, then I recommend you remove the air cleaner from the engine and soak it in kerosene, varsol, etc. It should let more air in than just a "whistle", I suspect it is still quite clogged. Some folks may think the screen you were talking about is the small screen located where the fuel line enters the carburetor; if that is correct, please clarify so we can continue to guide your efforts to resolve the issue.

[kully560]

it is the small screen on the carb. just past where the air filter hose enters the carb on the bottom under where the choke shaft is .

[Gary Dotson]

He’s referring to the drip screen just behind the choke plate, Rick.

[Rick Spivey]

Well, that's the screen I didn't think of! That clearly points to a needle/seat allowing too much gas into the carburetor; however, I once had a similar issue where the discharge nozzle was loose, and allowed fuel to keep flowing into the carburetor throat. Your carburetor needs a good review to insure proper function.