John Deere 4720 tractor won't start

[JAKAFUTZ]

I have a JD 4720 that cranks over but won't start. The last time it ran was two months ago and started just fine at that time. I've done a ton of research on this forum but haven't been able to figure it out. Most common problems have pointed to the solenoid or the thermistor. I tested every relay and checked all of the fuses and they're all ok. When I turn the key I can hear both the relay and the solenoid click. Many have suggested the thermistor so I pulled out the fuse box and took apart the wiring harness but I don't see anything remotely close to a thermistor. Could it be located elsewhere? Any other suggestions? I'm not an overly technical or mechanical guy but can figure things out fairly well if given a little guidance. Thanks.

 

[Jay4200]

Is your PTO lever engaged?

 

[JAKAFUTZ]

Good thought but it is not.

 

[DwayneB]

Has it got a fuel solenoid on the injection pump? I don't know much about the newer Tractors.. Injection pump or heiu injection?

 

[Dozernut]

Fuel filter plugged? Worth checking.

 

[dsb5610]

Open the bleed screw on the filter housing while someone cranks it over. Make sure there is no air coming out.

dsb

 

[JAKAFUTZ]

I had a spare fuel filter so I put that in and bled the air out. Plenty of gas flow so the solenoid is working fine. I think the next step is to check the safety switch. I'm not sure what else it could be.

 

[JAKAFUTZ]

Checked the safety switch and that is in working order. Any other suggestions?

 

[JD5210]

Sounds like you have covered a number of bases. Have you checked the air filter?

 

[thepumpguysc]

2.4L?? w/ integrated fuel system.. under the valve cover??
It sounds like the control rack is stuck??
REMOVE the shut off solenoid & reach in the hole & see if you can push/pull the rack..
There are videos online that will show you how it works..
Just google JD 2.4l fuel system..

 

[JAKAFUTZ]

Yes...new air filter. I'll see if I can figure out thepumpguysc's recommendation. I did Google the 2.4L fuel system but didn't see any videos that explained it. My JD 4720 is a 2007 so it does have the 2.4L engine with the integrated fuel system.

 

[JAKAFUTZ]

Also, if anyone has specific information about the thermistor on the JD 4720 I would love to know where it is. As I mentioned earlier...I took apart the fuse box completely and the harness behind it and didn't see one.

 

[thepumpguysc]

I watched the video this morning.. now I cant find it.. It was a JD supplemental video on utube..
Strange??

 

[diesal]

Did you solve the problem. My tractor uses mechanical fuel pump pretty much out of ideas. Where would fuel solenoid located? Any input would be appreciated

 

[JAKAFUTZ]

Yes...it was bad fuel. I drained the tank and replaced it with fresh diesel and it started right away. Good luck.