Carb problems?

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Carb problems?

Postby chuck1234 » Thu Oct 17, 2013 3:42 pm

Hi all,

First post here, though I've been lurking around here and there. I don't really know enough to provide helpful contributions (yet), but this site is an awesome resource and I look forward to your responses. Here's the deal-

My father and I own two Farmall Cubs, one of which is giving us a hard time. The ID plate's a little worn off, but it reads: "CUB 211385 J" if that helps ya'll get a picture of what I've got.

Anyway, this tractor ran beautifully all season last year and we haven't been able to get it running for 5 minutes this year. It cranks, it sometimes starts with a choke, runs for a few seconds, and dies. Here's what I've tried:

I suspect the gas tank is rusty, so to rule out bad gas I rigged a temporary pony tank to the carb with a new line, new filter, and fresh gas. Next, I disassembled the carb (just separated the body from the bowl) and cleaned out some gunk (mostly in the bowl assembly), put it all back together and in place. All good. Started right up and ran. Kept running. Still running (3-4 minutes)!--and kaput: shuts off and I've been unable to get her going again.

Next, I sprayed some starting fluid. With a shot, she starts right up (full choke), sounds great, then dies immediately--before I can even play the choke.

As you can imagine, this is a bit frusturating. My most recent thought was whether we should be treating the gas with ethanol treatment. We've never treated our before, but could this be a problem? Is the carburetor even the problem?

I can come back with pictures and any additional info you may need to help deduce the problem. Thanks for taking a look. Looking forward to any help!


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Re: Carb problems?

Postby Cecil » Thu Oct 17, 2013 6:39 pm

It sounds like the high speed jet has dirt in it. It is the brass bolt on the side of the carb. Remove it and run a SOFT piece of copper wire thru it.

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Re: Carb problems?

Postby Bob McCarty » Thu Oct 17, 2013 6:56 pm

When you have the jet out, turn on the gas and make sure you have a steady flow for at least a couple of cups worth. If you don't, the inline filter may be reducing flow, or the gas inlet filter screen may be clogged.

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Re: Carb problems?

Postby Rudi » Thu Oct 17, 2013 7:28 pm


G'day to you and hey .. 2 Cubs .. father and son .. excellent. Cubs are known to improve generational togetherness :wink: :D

Cecil and Bob have given you good advise. Two of the Cub Carb Guru's to be sure and that was proved again last weekend working on my Lo-Boy. If that don't clear up the problem, let us know.

In the meantime:

Image to :big smile: Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to :arrow: the Welcome Wagon wherein you will find links to many useful sites and topics. One of the most important resources are Owner's Manuals, Parts Catalogs and Service Manuals. The Cub Manual Server is the home of the jpg versions and the [url=[ Sorry, direct links to manual section is not allowed. ]/index.php]PDF Manuals[/url] -- well the pdf's of course :wink: Enjoy!.
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Re: Carb problems?

Postby chuck1234 » Tue Nov 19, 2013 9:39 am

Thanks for all your replies. I exhausted my limited know-how and brought the carb to a mechanic friend/shop who determined that the idle tube was bent and was limited flow. Fortunately, he happened to have a spare top half of an identical carb which we were able to put together on the cheap.

The good news is that she's back up and running. Well, sort of. Due to rust and debris in the gas tank, it's rigged to a pony tank strapped on the hood. A gas tank replacement/refurb is next...

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Re: Carb problems?

Postby Barnyard » Tue Nov 19, 2013 9:48 am

Keep the old top, the idle tube is rather easy to replace.
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Re: Carb problems?

Postby Rick Spivey » Tue Nov 19, 2013 6:10 pm

Hey Chuck,

Not to pick a fight but I don't think your bent idle tube is really the problem. It likely got bent when you separated the halves, which was after the symptoms appeared. I would be more inclined to think that the screen in the gas inlet on the top half of the carb is full of gunk from the tank. If not, something is inhibiting flow, as you are starving for rule once the bowl empties. When you changed top halves, voila. What condition is the screen on the sediment bowl in? I would clean the original top half, check that screen, and replace that idle tube. The two halves "should" stay together, as there were various versions, and sometimes mixing parts won't run optimally.
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