M120 wont shut off with key

cwaltz21

New member

Equipment
M120, M9000
Apr 23, 2024
2
0
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2018Ramtruck
I have an early M120, and tonight it repeatedly would not shut off with the key. I was chasing a different issue, where the engine smothers itself and almost stalls out when I'm pushing it hard(kick the clutch in, takes 5 seconds or so to come back to correct rpm) I cleaned sedimenter(ordering new seals tomorrow) and went to replace the fuel line between the tank and the sedimenter, but as things goes, I bought 3/8ths line instead of 7/16ths, so I reconnected the old line but obviously some air got in.

When I reattached the fuel line, I forgot to prime it(it was just one of THOSE afternoons), so after several trying to starts,hoping out,priming,trying to start,etc it fired up. I ran it back to the shed, went to shut it off and.....kept running. Gauges and electronics all go out, engine doesn't. Does shut off with manual kill switch.

Anyone have any issues with this on the early M120? I asked in another thread but the member hasn't been active in 11 years so I don't have my hopes up. That thread leads me to believe its either the shutoff solenoid, or a shorting wire in the steering column. Where is the solenoid? And yes, the last time I did throw up the steering column because I was starting to get heated.

If anyone has any advice on the engine smothering itself too I would greatly appreciate it, hoping its just the fuel lines sucking air and when I buy the correct new lines tomorrow that will be solved.

And one last question, when I was using the hand prime, fuel/air was bubbling up past the primer plunge...could that be the source of the air?

I do apologize for what might seem like easy questions, but with a little one coming in the next couple days, time is of the essence!
 

Russell King

Well-known member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
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Austin, Texas
There is probably a solenoid that controls the fuel flow that has a problem. It could be a fuse, wire problem or the solenoid itself.

sometimes the solenoid holds fuel on to run other version holds the fuel off. I have no idea which version your tractor is. You may be able to locate it and see if it is moving when you turn the key on or off. I believe it is near the injection pump.
 
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North Idaho Wolfman

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Lifetime Member

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
Your tractor does not have a fuel shut off solenoid, it has a fuel control motor.
You're going to need to get the WSM (aka Service manual) in order to troubleshoot the circuit.
This could also be the issue with it not running properly.
And yes you'll need to address the leak at the primer too as that can also be one of the possible issues.
 
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