Diesel Shut Off on 3720

Deere Dude · Aug 7, 2012

I have a 2010 JD 3720 and I read a few posts of people tipping tractors or getting oil in the engine and not being able to shut the motor off. The diesel would continue to run even after the switch is turned off.

I finally decided to try to shut down my tractor as if it had a run-a-way diesel. How in the world does that work? Do I even have to worry about it? I can shut it down with the key right now, but I understand some run under certain conditions even after the key is shut off so they need to put a rag over the air intake.

I had the hood up and there is no way to do that on mine, I don't think. If that fan blade is spinning I sure don't want to go near it with a hand or even a rag and there isn't a nice neat air intake hole to plug up..

Any ideas or am I worrying about nothing?

jenkinsph · Aug 8, 2012

Keep the tractor right side up and all will be well. If you are worried about it consider placing it on your homeowners insurance policy if you haven't done this.

Deere Dude · Aug 8, 2012

jenkinsph said:
Keep the tractor right side up and all will be well. If you are worried about it consider placing it on your homeowners insurance policy if you haven't done this.

It its just a preventative measure. Just for kix I tried to shut it off by restricting air flow but there was no way I could even slow it down. I surely am not seeing something right.

dschuffert · Aug 8, 2012

All the key does is remove power to a solenoid that then closes the fuel supply. You can reach into the engine compartment and manually remove the wire from the solenoid to get the same effect.

In your manual one of the prep tests for the tractor when it is new is to block the air input. When you do this an air restriction light will illuminate on your dash. If the restriction light does not illuminate it is either a air pressure switch or an air leak in the system. Did your air restriction light illuminate when you did your test?

Deere Dude · Aug 9, 2012

dschuffert said:
All the key does is remove power to a solenoid that then closes the fuel supply. You can reach into the engine compartment and manually remove the wire from the solenoid to get the same effect.

In your manual one of the prep tests for the tractor when it is new is to block the air input. When you do this an air restriction light will illuminate on your dash. If the restriction light does not illuminate it is either a air pressure switch or an air leak in the system. Did your air restriction light illuminate when you did your test?

I looked in the manual and it says to use a piece of cardboard or something solid over air intake, then a light will come on, it says. I used a rag but that may have let air through because it is porous. I'll try it again today again. Thanks.

Rara Avis · Aug 11, 2012

Deere Dude said:
I have a 2010 JD 3720 and I read a few posts of people tipping tractors or getting oil in the engine and not being able to shut the motor off. The diesel would continue to run even after the switch is turned off.

I finally decided to try to shut down my tractor as if it had a run-a-way diesel. How in the world does that work? Do I even have to worry about it? I can shut it down with the key right now, but I understand some run under certain conditions even after the key is shut off so they need to put a rag over the air intake.

I had the hood up and there is no way to do that on mine, I don't think. If that fan blade is spinning I sure don't want to go near it with a hand or even a rag and there isn't a nice neat air intake hole to plug up..

Any ideas or am I worrying about nothing?

In an emergency, a CO2 Fire Extinguisher expended into the air intake will shutdown a runaway diesel...