cub farmall wont stay running

Anonymous-0 · Feb 20, 2012

have an older guy that im helping with his cub..hasnt run in a number of years..took carb off put in new kit..tractor will start but not pick up..acts like its not getting gas..plugs are not wet ...will run for short amt of time..like 4 or 5 seconds then dies..have to choke to get it started...doesnt sound like all cyl are hitting..took diff carb off of a parts tractor and went thru it and same symptoms..havent checked compression yet suspect possible stuck valve putting pressure back to carb?..any ideas?..thanks in advance

Oldiron29 · Feb 20, 2012

deene, How is the gas flow from the tank?
Sounds like main jet is cloged. Did you run a fine wire down it? oldiron29

Harold Evans · Feb 20, 2012

Check for rust in the gas tank. Even the smallest pieces can cause these symptoms. Also, check to see if there is an inline paper filter and remove it. They get clogged very easily. No need for them in a gravity fed system with a sediment bowl. I have repaired two tractors with these same problems by removing the tank, cleaning it well, and applying a coat of plastic sealer to the inside of the tank. Not a single problem with either of them since then.

El Toro · Feb 20, 2012

Hold your hand over the throat of the carburetor while a helper try's to make a start. If you don't have good suction means you have low intake manifold vacuum. Could be a vacuum leak
around the intake manifold. I would check the compression too. Hal

Brad Gyde · Feb 20, 2012

(quoted from post at 19:12:08 02/20/12) deene, How is the gas flow from the tank?
Sounds like main jet is cloged. Did you run a fine wire down it? oldiron29

I had a similar problem with my Cub.. It needed carb work when I bought it, so I bought a NEW carb, installed it, new sed. bowl, and new fuel line.. Tank was clean..

Mine would run for a bit, then act up.. No determined time until it would act up, but it was a guarantee it would.. Pull the choke out more and more and more, eventually it would just up and quit.. Pull the fuel line off at the carb, seemed to be good flow..

I fought with it for days, finally one day, I ran it with the fuel cap loose, and it ran fine, under load, for almost a hour mowing.. Cleaned the vent good in the cap and has been fine ever since. Only thing I can think is when I disconnected the fuel line, it'd let some air to the tank quickly before I noticed, and would flow a good stream long enough for me to decide I had good flow.

Brad

Jim in Ma. · Feb 20, 2012

Have you checked the oil bath for the air cleaner?

Janicholson · Feb 20, 2012

Make sure the fuel line screen at the carb fitting is clean. the main jets are often partially plugged and need soaking and a thin wire to assure they are clean. As fuel evaporates in the carb while sitting in the barn, it concentrates solids and they form varnishes that plug the passages. Good luck. Jim

cub farmall wont stay running

Anonymous-0

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Oldiron29

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Harold Evans

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El Toro

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Brad Gyde

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Jim in Ma.

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Janicholson

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