656 carburetor

Bob And · Mar 13, 2009

I"m wondering about what I call an automatic mixture control on the carburetor on a 656 Farmall. Can this be replaced with the manual adjusting screw commonly found on most IH carburetors and if so, will the needle seat need to be replaced? My 400 came from the factory with one of these and the dealer replaced it with the standard adjustment screw, but that was a long time ago!!!

the tractor vet · Mar 13, 2009

It is called a shut down solenoid and it is to shut the flow of gas thru the main jet so the engine will not diesel. and it is best left in place in working condition . As the engine could kick back and cause a fire or it may diesel and give ya fits on shut down. Now in all my years of working on I H tractors i have never in my life seen a shut down solenoid on any 400 -450 -460- 560 gas tractor . They did not start using them till the 06, 04 in 1963 and newer .

karl f · Mar 13, 2009

Should still be available new from caseih. helps if you bring in carb, carb tag, old part, or if you can identify whether you have IH, marvel, or zenith carb.
if you still have problems, check your wiring. the wiring harnesses on our 656 corroded up really bad under the dash in the circuit for coil, warning lights/gauges and carburetor solenoid, and was giving intermittent problems.
in the 28 years i've known the tractor, we've gone in spurts with that solenoid, a few in a row then for about 10 years without. earlier "failures" may have been due to the wiring issue.

issues with how it runs can be fuel supply (tank, lines, vent) air filter, worn throttle shaft, internal part damage of carburetor, heat riser failure, worn distributor bushings, and/or distributor cam lobes. also worn out engine...

good luck
karl f

Bob And · Mar 13, 2009

Thanks for the replies guys. I guess I didn't think about it being a shut off solenoid. I know about them on small gas engines. It's on my son's tractor but I didn't see any wiring to it so that's probably the problem. Concerning my 400, I know that when we first got it from the dealer there wasn't a mixture control screw on the carb, there was something in/on the carb that was supposed to regulate the fuel mixture according to the load. However it used 5 gal an hour no matter what it was pulling. We took it back to the dealer and they put in the mixture adjustment screw which worked a lot better.

bc · Mar 13, 2009

I replaced the solonoid on my 2606. Just need the screw, nut, and packing you can order off a similar carb. My old solonoid had an adjusting screw on it and the wire was long gone and where the wire went in it was all rusted. They don't make them with the adjusting screw anymore. I kill the tractor with a valve on the fuel line so it doesn't matter about dieseling and I don't have gas leaking out the carb.

I'd suggest using the adjusting screw and a shutoff in the gas line anyway.

Owen Aaland · Mar 14, 2009

If there no longer is any wire attached to it most likely the needle has been cut off inside. Otherwise it would always have the fuel shut off.

bc · Mar 15, 2009

Mine still had the needle on it. They put an oring on the threaded part and screwed the whole thing in. Basically used the whole solonoid to adjust the needle by screwing it in or out till it was running right. Sometimes hard to keep it from leaking past the oring and threads though which is part of the reason why I replaced it with a needle.

rustyfarmall · Mar 15, 2009

The new solenoids you can get today are non-adjustable. The thing is either all the way open or all the way closed. If you are doing light duty work, the all the way open position can result in an over rich fuel mixture and will most likely foul the spark plugs and dirty up the engine. The packing, packing nut, and adjustment screw from an earlier carburetor will replace that solenoid, and then you have the ability to fine tune the fuel mixture, which will result in a much better running tractor.

656 carburetor

Bob And

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the tractor vet

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karl f

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Bob And

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bc

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Owen Aaland

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bc

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rustyfarmall

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