Farmall 656 gas Carb

fordfx413 · Mar 8, 2018

Working on a 656 gas with a IH carb. Engine was running ruff and has poor throttle response. I'm looking over everything and doing a tune up. I noticed gas leaking from the carb on the inlet side. I pulled the carb and im installing a new needle assembly. I noticed the needle on the fuel shut off solenoid is cut off. Could of the mixture of been too rich with it cut off like that? I found a manual main fuel valve on this website that i might replace the solenoid with. What is the best adjustment for the manual fuel valve? Thank you

Janicholson · Mar 8, 2018

The adjustment of a needle replacement will be unique to each carb. I would turn it out 5 turns and start it. Remember the electric device was to shut off the fuel flow at shutdown. At rated load (full power pulling a plow) the exhaust should be just barely leaner than showing a whisp of dark smoke. It should pickup from idle with no stumble when a bit warmed up. Jim

fordfx413 · Mar 8, 2018

Ok thank you. Somebody before me had cut the needle off the solenoid and had disconnected it from the circuit. So the only this it is doing is acting like a plug.. In my IT manual it shows a solenoid that is adjustable so i was wondering if the fuel- air mixture was too rich.

fastfarmall · Mar 8, 2018

I bought a new 656 gas new in the fall 66, i loved the tractor but it spit and sputtered when it was still on warranty,but i didn't use the premium grade of gas either,and i admit i didn't read the owners manual either.

BarnyardEngineering · Mar 8, 2018

Since that's the "load needle" on older versions of the same carb, I would say yes, cutting it off probably caused the engine to run extremely rich.

pete 23 · Mar 8, 2018

I would only run rich if someone installed larger main jet or drilled out original as they all come with calibrated main jet that is to be totally unrestricted when used under full load. The reason someone cut off that electric shut off is that they give problems and new ones cost an arm and a leg.

No reason a replacement adjustable needle will not work though. Just don't try to wean it much unless you want valve and piston problems.

the tractor vet · Mar 9, 2018

They cut the neddel off because it probably went bad and would not open and to cheap to replace it . On the I H gas engines of that era that solenoid was for shut down only , yes the vary first ones were adjustable . But the problem of putting and adjusting screw on it lead to people ADJUSTING it lean and toasting there engines so they made them non adjustable and like Pete said it was jetted for max use . Back in those days engine run on was common when shutting down a gas engine when hot or if the curb idle was set to high , many cars and trucks of that time frame had a throttle solenoid that once you turned the key to the run possession it would set to MFG curb idle and when you turned the key off the solenoid would retract and close the throttle plates closed stopping the air and fuel flow to the cylinders , on the I H carbs the pintel would go into the main jet and stop the fuel flow and help shut down the engine when hot . So there for it is wise to leave well enough alone and keep it working . I never try and wean and engine back if anything i may fatten them up a bit .

Farmall 656 gas Carb

fordfx413

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Janicholson

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fordfx413

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fastfarmall

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BarnyardEngineering

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pete 23

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the tractor vet

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