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Having some issues getting 1969 Farmall 656 gas tractor to start


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I am having some issues getting my 1969 Farmall 656 gas tractor to start. When I go to start the tractor, the engine turns over just fine. The engine then shows faint signs of firing for maybe one or two seconds, but this faint firing never sustains itself beyond one or two seconds. What might I consider looking into to troubleshoot? Here is my troubleshooting plan:

1) After attempting to start the tractor, remove the spark plugs and see if they are wet. If they are completely dry, this means that fuel is not getting to the engine. If this is the case, tap on the carburetor to loosen what may be a stuck needle valve.
2) Remove the spark plugs, connect the spark plugs to their respective spark plug wires, touch each spark plug ground to a grounding surface, try starting the tractor, and finally make sure that each spark plug is sparking. If not all spark plugs are sparking, inspect the distributor. Consider replacing the rotor and cap.

Right before I started encountering this starting issue, I did have an electrical wire (18- or 20-gauge in thickness) break. This wire went from the battery's positive terminal to somewhere behind the instrument panel / dashboard. The break occurred somewhere behind the instrument panel. My current information (which I can't guarantee is fully correct) indicates this wire breaking should have no bearing on why my tractor is not starting because: 1) This wire appears to have nothing to do with ensuring the spark plugs are getting spark, and 2) I suspect this wire may have been added after the tractor left the factory given that I am not seeing this wire on the wiring diagrams I have looked at.

What are your thoughts? Is there anything else I might add to my troubleshooting plan? Can I rule out that wire breaking as a potential cause of these starting issues? Thank you much.

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If this started right after that wire broke, it might very well be the source of the problem.  Have you put that wire back together to see if that makes any difference?

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If it's trying to start, sounds to me like fuel. There is a solenoid hanging out the bottom of your carb at an angle. If you unscrew that out, it will show if there is any gas in the bowl. You can also check it to make sure it is working and not plugged. If you turn the key off and on, you should hear it click each time. That is the solenoid pushing the plunger in and out. If you unscrew it out, plug it back in, and you can ground the body against something and watch it operate.

If you take it out and the bowl is full of gas, then it is working alright.

Have you done anything fuel related to it lately?

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3 minutes ago, Duntongw said:

If it's trying to start, sounds to me like fuel. There is a solenoid hanging out the bottom of your carb at an angle. If you unscrew that out, it will show if there is any gas in the bowl. You can also check it to make sure it is working and not plugged. If you turn the key off and on, you should hear it click each time. That is the solenoid pushing the plunger in and out. If you unscrew it out, plug it back in, and you can ground the body against something and watch it operate.

If you take it out and the bowl is full of gas, then it is working alright.

Have you done anything fuel related to it lately?

Good thought.  If that solenoid quits, it sure won't start.  Remove it, hold finger over the hole to plug it, and try to start it.  See if that makes any difference.

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My 656 wouldn’t start this spring either. Confirm if it’s fuel related by trying ether. If it still doesn’t show signs of life it’s the ignition. I put electronic ignition and a new coil on mine and it started easily, even with one cylinder not firing. A different distributor cap got all six going.

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I'd like to try reconnecting that wire... I just can't see what it connects to!  (it goes to somewhere behind the instrument panel, that much I know)

Checking the carburetor solenoid:  excellent idea.  I have not tried that.  It would be nice to at least rule out any fuel related issues, that way I could just turn my attention to the ignition system.  Nope, haven't done anything fuel related lately.

Sure, I can try removing the solenoid and just plug the vacant hole with my finger.  If that gets the engine's firing to sustain, I guess that would mean the solenoid is the issue.

I'll give the ether trick a try.  Right, that would be an easy way to rule out the ignition system as the culprit.

Doubt I'll get around to trying any of these tips anytime very soon, though.  All great tips, but it's looking like they'll need to wait a few weeks until my work schedule finally calms down and lets me have a life outside of work again!

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Yeah, sorry, nothing to report on currently.  Crazy busy work schedule has prevented me from tending to this.  Heh, at this point (given my lack of time) I'll probably just call someone to come look at the tractor.  Still, I appreciate all the recommendations.

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