carb

[dterhaar2000]

I bought a 52' cub about two weeks ago. It ran ok but needed a head gasket, when I got the head gasket I went ahead a bought a new carb. The carb I bought matched the one I had perfectly. I put the carb on and it ran really good. Now it wont start and gas is dripping from the carb very steady. Is there something i'm missing or forgot to do? I drained the gas and put fresh in, hooked choke and throttle rods up how they were, and put a new fuel filter on. Help is greatly appreciated. thanks

[Slim140]

Probably need to adjust the float. Is it a Chinese carb or an IH carb?

[Stanton]

Welcome!

Sounds like you have it flooded and/or the float is not causing the needle valve to close off fuel flow to the carb.


There are several fuel and carb-related threads in the How To Forum, located here:
http://www.farmallcub.com/phpBB2/viewforum.php?f=139

When you have some time, read through a few threads to acquaint yourself with the Forum:

• Welcome Wagon
• How to Upload Pictures to a Post
• Forum Picture Posting And Other Interesting Things You Can Do
• Using the Forum

After your 2nd post on the Forum, you'll have access to the all the free PDF Manuals. They are located via "Quick Links" in the upper left corner of your screen. Hit that and a pull-down appears where you'll find "PDF Manuals". Through that link, you'll be able to download an Owner's Manual (very strongly recommended) and any service manuals that interest you. You'll be able to familiarize yourself with your new-to-you Cub more quickly. Implement Manuals are also available.

Might also enjoy reading through this thread: What to do with a Cub you just brought home

Take some pictures of your tractor and post them. We’d like to see it.

Glad you joined us.

[Don McCombs]

Common problem with the Chinese knock-off carbs. Use these dimensions to check/set the float height.

[Glen]

Hi,
The needle and seat might have dirt in them, and not seal, causing the dripping. You have to take the top off of the carburetor to clean the needle and seat.

Here is info for setting the float height, and float drop, for the IH carburetor, and removing the top half of the carb.

The IH carburetor is easy to work on.
The top half has to be taken off the carb to set the float level.
When taking the top half off the carb, pull it straight off the bottom half 3 or 4 inches, there is a small idle tube that is screwed into the top half, that sticks down into the bottom half. If you twist the halves, or strain the tube too much, it can break off. Then you have to buy a new tube and repair that.
Below is a page from the Cub service manual, showing the float level, and float drop for the IH carburetor, in the upper pics. It should be set to exactly the specs shown.
The top half has to be removed from the carb, and turned upside down, like the pic of the Zenith carb, on the lower right of the page.
Bend the float arm, between the float and the pivot to change the float height, but not right where the end of the needle touches it.
Be sure to use the specs for the IH carb. Don posted them above also.

Turn the top half right side up to set the float drop.
The tab on the float is for the float drop, it stops the float from dropping too far. Bend the tab to change the float drop.
You need a measure with 32nds of an inch markings.

http://www.farmallcub.info/manuals/gss- ... 002-09.jpg

The IH carb float level is measured without the gasket between the halves in place.
People have posted on here that their carbs would not work right, until they set the float level exactly.
Tighten the screws and everything on the carb gently, the metal is soft, and the threads can strip.

[dterhaar2000]

I took the carb off and it had a bunch of rust from the air cleaner in it, I cleaned the air cleaner but there is no oil in it for the oil bath. Can I pour some in or does it have to come from the engine?, there is a tube coming from the block to the air cleaner.

[Bob McCarty]

You should add oil up to the seam in the air cleaner cup. The vent tube often gets clogged up, so it's a good idea to remove it and see if it's open. String trimmer works good to clear it out.

[Dale Finch]

You should add oil up to the seam in the air cleaner cup. The vent tube often gets clogged up, so it's a good idea to remove it and see if it's open. String trimmer works good to clear it out.

Just to clarify, I believe the "seam" Bob mentioned is the beaded ring around the cup below the upper edge, not all the way to the top.

[Glen]

Hi,
Below is the 1955 Cub owner's manual. The experts on here recommend reading it, it has lots of info about operation, maintenance, and lubrication. There is a table of contents on page 1.

http://farmallcub.com/rudi_cub/www.clea ... index.html

The manual shows cleaning the air cleaner on page 36.
The air cleaner needs removing from the tractor, and washing out with kerosene to clean it after the number of hours shown in the manual.
The inner material does not come out of it, I pour in some kerosene, with it upside down, and put the oil cup on it, without any oil in it, and shake it to wash the inside. Turn it different positions and shake it. Then remove the oil cup, and dump out the kerosene. If you dump it into a clean oil drain pan, you can see what was in the air cleaner. If it was dirty, repeat rinsing it.
The kerosene will probably run out the connection for the hose to the carburetor with the air cleaner upside down. Plug the connection with duct tape, or something during the rinsing.

This manual has the same electrical system info as a 1952 Cub would have originally come with, the 6 volt, positive ground system.
The Fast Hitch shown in it was available starting in late 1954.
There is a 1952 Cub owner's manual at the top of the page, at Quick links, then go to PDF Manuals.
I can't post a link to it here.

There are 3 gear housings in the rear of a Cub that need the oils checked, or changed, if they haven't been changed lately. Using the Cub with low oil can damage the parts in the housings.
They are the transmission, and 2 final drives. Each has a separate oil to check.
The transmission can get water in it, from rain, or condensation inside the case, over time.
The owner's manual shows where the oil plugs are, and how to change the oils.
There are other oils also to check and change.

[ShawnAgne]

My 300 started doing exactly what you are describing this past early summer. Needle was stuck and it was flooding. When I got a new rebuild kit fixed all the issues.

[dterhaar2000]

I put oil in the oil bath. I still cant get it to start. I took the carb back off, opened it, float was good and not stuck, so I cleaned it anyway. Its still flooding out. I put the original carb back on and its doing the same thing still. What am I missing? its getting frustrating.

[Bob McCarty]

Did you remove the needle valve to make sure there was no debris in the seat? When you remove the float to check the needle valve, dip the float in hot water; if you see a bubble stream the float is leaking. Did you adjust the float height and drop and make sure the float was centered in the bowl?

[dterhaar2000]

yeah, its centered. I didn't take the needle valve out. It doesn't seem to be flooding as bad however, it still won't start. The plugs are getting spark, its getting fuel, it sucks on my hand if I cover the carb with my hand. I'm not sure what else to try. Could the carb still be at fault or can it be something else?

[Bob McCarty]

Have you removed the main jet on the old carb and run a thin copper wire through it to make sure it's clean? Try spraying some carb cleaner into the air intake with the gas shut off. If the tractor starts, it's probably fuel, if not, electrical (points, condensor, plugs, firing order, etc. Are you sure the new fuel filter is for a gravity fed fuel supply (like a lawn mower) and not for a fuel pump system?
Flooding is caused either by the needle valve not seating and sealing, or a problem with the float.

[Glen]

Hi,
The new carburetor might have dirt in the needle and seat, making the needle valve not seal, and drip on the ground. Even a tiny piece of dirt will keep it from sealing.
I would take the needle valve out of the seat, and look at it, see if it looks normal, no scratches on the pointed end, and clean it with carburetor cleaner, if dirty, and a clean cloth.

Look in the seat also with a light. Clean down in the seat, with carburetor cleaner, if dirty, and a clean cloth pushed in with a Q Tip or something that will not scratch the seat.

The needle and seat wear after years of use, then they don't seal anymore and the carb drips on the ground when the Cub is sitting. Check the pointed end for wear, the new one won't be worn, but the old one could be. They need replacing when worn and leaking.

Below is a listing at TM Tractor for a new needle and seat, you can see what it looks like there.

http://www.tmtractor.com/new/fl/5183fp.htm

A Cub will usually drip some gas on the ground out of the drip hole under the carb, after you try to start it, turning the engine several times, and it doesn't start. It should stop dripping soon though, if you don't turn the engine more. It is an updraft carb, that it how they work.