farmall 350 surges on idle

gordy from Iowa · May 7, 2016

The tractor runs fine on anything over idle, but surges up and down on idle. I have turned the idle screw clear in and backed it off one turn like the manual says. What can I check next? Thanks for the halp..

showcrop · May 7, 2016

That is called hunting. For some engines like old Detroits it is normal until they warm up a little. Otherwi8se than that it usually indicates wear in the governor or linkage. linkage is easier to repair than the governor itself so check the linkage for worn places first.

old · May 7, 2016

The idle adjustment works backwards so the more you open it the leaning it gets. The idle circuit of the carb maybe clogged up a bit or the gov maybe out of adjustment. If choking it a bit at idle helps then you have a clog some place.

David G · May 7, 2016

It is either running lean or governor having issues, I would be issue with idle circuit.

pete 23 · May 7, 2016

It will depend on which carburetor you have as to which direction you turn idle mixture screw. If it has a large screw that is down a bit from mounting flange, it is an air screw and turning out gives more air. If smaller screw right up in the flange it is a mixture screw and turning out enriches mixture. At any rate, forget about the one turn. That is just a general starting point. Always set where engine idles best. It sounds like you are running rich at idle and will need to repair carburetor. If it does not smoke slightly black from running rich, it might be lean and sucking air around manifold also.

hadley · May 7, 2016

(quoted from post at 21:27:57 05/07/16) It will depend on which carburetor you have as to which direction you turn idle mixture screw. If it has a large screw that is down a bit from mounting flange, it is an air screw and turning out gives more air. If smaller screw right up in the flange it is a mixture screw and turning out enriches mixture. At any rate, forget about the one turn. That is just a general starting point. Always set where engine idles best. It sounds like you are running rich at idle and will need to repair carburetor. If it does not smoke slightly black from running rich, it might be lean and sucking air around manifold also.

he M we have did that. Turned out manifold was cracked the whole way around one end on exhaust but near the middle. Put on a different manifold and it fixed it. Purrs like a kitten at idle now.

gordy from Iowa · May 8, 2016

Thanks for the help guys. I'll check it out and let you know.

farmall 350 surges on idle

gordy from Iowa

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showcrop

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old

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David G

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pete 23

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hadley

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gordy from Iowa

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