melt down

[jdeere86]

Hey guys

Was trying to get the cub with the basket weeder going tonight so i could plant some lettuce. shes a crank start. flooded her good ... kept cranking and cranking swearing waiting then cranking .. full choke..no choke ..partial choke ..swearing .. cranking ..swearing ..cranking ...finally got her to fire ...once fired she runs great. guessing since once running and she runs good it's not a carb issue? was thinking of taking carb apart cause part of the gasket on the corner of the bowl seems to be missing ... any thoughts or suggestions would be greatly appreciated ...love you all..would be lost without this forum

[Glen]

Hi,
Here is some info for cleaning and repairing the IH carburetor, if you need it.
You might not need all the info, if the carb has been cleaned lately, but it's important to set the float level right.

Before taking the carb apart, clean the outside of it, to keep dirt out of the carb.
When taking it apart, pull the 2 halves of the carb straight apart several inches, there is a small idle tube that screws into the top half of the carb, and sticks down into the bottom half of the carb, it can break if you twist it, or don't pull the 2 halves straight apart.

Use carb cleaner, or solvent to clean inside the carb.
All the passages need to be open and clean.
Blow them out with compressed air, and be sure they are open. Use your safety goggles when using the air.
Remove the main jet, the 6 sided brass colored part low on the side of the carb, and run a small wire in the hole in the end of it, to be sure it is open, and then wash the jet.
Tighten it gently, it can break. It should have a fiber washer under the head, to seal it, sometimes if the washer is old, it won't seal if you reuse it.

The needle and seat could have dirt in it, making it not seal. Remove the float and the needle and check for dirt, clean the needle and seat.
Check the float, it should look in good condition, not collapsed or corroded.
Shake it gently while it is off, it has to be dry inside, no gas inside it.
If it is good, it can be used again.
Assemble the needle and float again.

The tab on the float arm has to face up.
Sometimes the float is upside down.
Put it in the right way, if it is upside down.

It is important that the float level and float drop be set exactly.
People on here have said that their carb wouldn't work right until they set the float level exactly.

Below is a page from the Cub and LoBoy service manual showing setting the float height.
The IH carburetor is in the upper pics on the page, the Zenith carb in the lower pics.
To set the float level, turn the top half of the carb upside down, like the pic of the Zenith carb, in the lower right of the page.
Don't use the float level specs shown for the Zenith carb, for an IH carb, they are different.
The gasket between the halves has to be off, when measuring the float level of the IH carb.

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

Bob McCarty converted the measurements to use a dial caliper, it is easier.
The float level is 1.4"
The float drop is 1.6"

Bend the float arm between the float and where the needle touches it, to change the float height.

Turn the top half right side up to set the float drop.
Bend the tab in or out to change the float drop.

The needle and seat could be wornout from years of use, and don't seal, then the carb can drip on the ground when the Cub is sitting.
I have seen them that were wornout, they dripped, and then it quit dripping after putting in new ones.
The IH carb has a small screen where the gas line attaches to the carb, be sure it is clean.
Tighten everything on the carb gently, the IH carb is soft metal, and threads can strip.
The carb top can warp if the screws are tightened too much.
You could check the gasket surface of the top when it is off using a straight edge.
TM Tractor, at the bottom of the page, has new carb parts.

Below are pages from the Cub parts manual showing the IH carb.
The main jet is number 28 in the pic.

http://www.farmallcub.info/manuals/cub_ ... 012-12.jpg

http://www.farmallcub.info/manuals/cub_ ... 012-13.jpg

Cubs have a manual choke, you have to use the right amount of choke when the engine is cold, until it warms up, so it runs good.

Below is a pic of an IH carb float from TM Tractor, showing the tab for the float drop.
The 2nd pic shows cleaning the main jet.

[Jim Becker]

You may not have anything to be concerned about. Since it had been sitting for a long time, the cylinders may have been dry and not sealing well. A few squirts of oil into each cylinder through the spark plug holes might have made things go a lot better. You might want to do a dry/wet compression test to see where you are on ring/cylinder wear.

[jdeere86]

as the carb does drip ill check needle and seat...

what kind of oil should I squirt into the cylinders?

dumb question..can compression improve just by running her or running some sea foam in the gas

thank you!

[Jim Becker]

I assume you mean the carburetor drips when the engine is not running, as long as the tank valve is open. If so, yes the needle and seat is almost always the problem.

Any sort of motor oil can be squirted in. You could even use something like Marvel Mystery Oil. You just want to get some fresh lubrication on the rings that will slow the passing of air past the pistons.

Just running it will help because once it is running motor oil gets distributed into the cylinders from the bottom. Putting any of the oily additives to the gas probably won't make a big difference, but that is one of the claims made for those products. They can help free up rings that are stuck in their grooves. Of course, a worn out engine will still be a worn out engine.

[jdeere86]

Thank you guys! Have some homework for tomorrow!

[k hutchins]

I know you said it flooded while you were cranking it, but were you getting good spark? Was it coughing at all during the cranking process?
I've had to crank mine (esp in cold weather) until l thought my arm would fall off. Yes the carb would flood, and it would cough every once in a while. As l got older and learned more about it, l found that the problem was electrical. New points, plugs, and condensor along with a new rotor button and cap made a world of difference. Mine has a mag so a new battery wouldn't have done anything, but if yours has a distributor, a new battery could provide increased spark. After a good tune up, half a revolution is enough to get it to fire.

Just more food for thought

[jdeere86]

Wasn't coughing until a little ways into it. I suspected could be electrical as once it did fire she ran great. I'll order the basic tune up kit as its only $15 -- can't hurt. Should mention that at one point in time I could easily get her to fire with one crank full choke and then one crank partial choke.

[NJ Farmer]

I’m thinking your idle tube is either plugged up or possible broken off. Either way you need to open the carburetor up and overhaul it with a new gasket kit and set everything back to specs (float drop, and check for correct idle discharge tube and main metering jet) there are three different model carbs that will go on a Cub. 2 models have specific parts required for the model number stamped on the top of the lid.
Use the IH service manual fuel system chapter to help you navigate the process.

NJ farmer

[inairam]

I am not sure if swearing helps but I do use that tool a lot when I am alone.

[jdeere86]

I'm going to take apart the carb later on today. I have a kit that I only used the gasket out of i believe and i have gasket making material that i'll use for a new one. Once I get going with the swearing it seems to escalate and becomes hard to stop. called the wife out to the tractor yesterday in hopes that it'd calm down my shouting and swearing. maybe it was her good vibes that finally got her to fire. ha

[Eugene]

Guessing since once running and she runs good it's not a carb issue?
Part of the gasket on the corner of the bowl seems to be missing.

Repair the carburetor. Missing gasket will upset the air flow through the ventura.

[jdeere86]

Will do. Took carb off after work today and started cleaning it. Was hoping to get it back together tonight ...looks like tomorrow. Dumb question..any tips for getting the pin out that holds the float? seems a little corroded ..sprayed some penetrating oil on it for time being til i get at her tomorrow

[Stanton]

You can remove the pin by tapping it out from either side. Use a small punch or nail; gently.

There are excellent threads in the How To section on carb cleaning and float height adjustment.

http://farmallcub.com/phpBB2/viewforum.php?f=139

[Don McCombs]

You can remove the pin by tapping it out from either side. Use a small punch or nail; gently.

Make sure that you provide good support for the pin posts when you tap on the pin. They are the same soft metal as the rest of the carb.