4300 no start issue.

[kc8ksg]

Last fall my 4300 hst started with not wanting to start after working it all day then letting it set over night. After a bunch of searching I did some testing and found somewhere to try shorting the white wire going to your shutoff solenoid and it will force the plunger back in. I did and it worked, so it seemed my shutoff solenoid was fine and I just needed a thermistor.

It wasn't a big deal to short that wire once and a while so that's what I did, here a few weeks ago it got a lot worse and wouldn't start unless you shorted the white wire so I ordered a new thermistor.

It worked great and fired up every time but twice since I replaced it it won't start. It's a lot better than it was before replacing the thermistor, but still something isn't right, and if you short the white wire it fires up every time which is what has me puzzled.

The only other thing I can maybe think is my shutoff solenoid is getting weak, I might try pulling it off and cleaning it to see if that helps but figured I'd ask and see if anyone had any insight.

Thanks

 

[Harry in Ky]

I've seen a number of questions here regarding Deere tractors and their famous thermistors, and although I believe I understand the concept, I'm not sure I agree with it. If your fuel shutoff has only two wires, one power and one ground, then I guess it's all you have. If it's a three wire coil, with one circuit to pull the plunger in, and the other circuit a low draw hold coil, you may have some options. If by "shorting the white wire" you mean temporarily applying 12v, then you could do this with a simple 4 pin relay. Add in a circuit to supply battery positive to said white wire through the relay and use the start signal circuit to energize the relay coil. Not exactly a "factory" fix, but it will do what your "shorting" proceedure does, and do it every time you engage the starter.

 

[kc8ksg]

It's a three wire with the pull in. Shorting isn't really the correct terminology that's my fault for wording it that way, basically I'm grounding the white wire out. I have thought about running a momentary push button to the white wire to basically do the same thing, but figured if I could fix it the right way first I would, if not do it my way.

 

[BRBurns]

My 4300 would not start yesterday either. It had done that before, but if I let it set a few minutes it would always start. This time it didn't. I didn't know about grounding the white wire. But I did know that it could be the solenoid not getting enough power. So I hooked up jumper cables to my truck, running, knowing that this would get the entire tractor 2 more volts. It popped right off and has started dozens of times since. I need to get a spare thermister.

 

[BRBurns]

It did it again this morning and hooking up jumper cables did nothing. Grounding the white wire did the trick. Going to pick up a thermister today.

 

[kc8ksg]

The thermistor did help but so far since it's been in there it hasn't started and I've had to jump the white wire twice. Before the thermistor it got so bad I had to jump it every time.

There have been a handful of times it hasn't started on the first try and after 30 seconds or so it will fire up, the two times I jumped the wire I only waited about a minute and got impatient and jumped it because I was working and didn't want to waste time to see if it'd eventually start on it's own.

Good luck, hope it fixes yours.

 

[Husaria Farm]

I also have a thermistor problem with my JD 4600. When I removed it and "hot" wired the two wires together it started on first try. Afterward it ran until I shut it off. When I tried to restart using the same method the wires got hot and smoked but no start occurred. Did I do some further damage? I'm expecting a new thermistor tomorrow. If that doesn't work, where should I look?

 

[BRBurns]

I think you probably smoked the fuel shutoff solenoid by hot wiring it like that. I'm guessing it can't Handel the full amperage on the solenoid the full time it is running. That is why they put the thermister there. It gets full amperage for a second or two until the thermister heats up and cuts back the amperage.

 

[Husaria Farm]

Thanks BR. That's what I was afraid of. Next purchase looks like fuel shutoff solenoid.

 

[JD755]

Correct that full time current to the pull-in coil on the solenoid will quickly burn it up. It takes a lot of current. JD has used various schemes such as thermistors and time delay circuits to limit the current to just a brief period. The most basic method was used on my 755. It simply connected the pull-in coil to the starter. Very basic and no problems with electronic components. You should do a repair on yours to make it as it came from the factory, but if not then simply connect the pull-in coil to the starter. No relay required.

 

[kebo]

My 4300 would not start yesterday either. It had done that before, but if I let it set a few minutes it would always start. This time it didn't. I didn't know about grounding the white wire. But I did know that it could be the solenoid not getting enough power. So I hooked up jumper cables to my truck, running, knowing that this would get the entire tractor 2 more volts. It popped right off and has started dozens of times since. I need to get a spare thermister.

My suggestion would be to start cleaning ALL of the electrical connections that you possibly can, especially the ones that handle the high starting current. Also, check the battery voltage and starting ampacity to make sure it's up to snuff. You would be surprised how much voltage all those low resistance connection points will drop, from the battery (source) to the load, and at the same time they tend to limit the current flow.

 

[rboss75]

Try the fuel shut off relay in the fuse panel. When you first turn the key you should hear a click before starting the machine. If you don't hear it it is your relay

 

[BRBurns]

My suggestion would be to start cleaning ALL of the electrical connections that you possibly can, especially the ones that handle the high starting current. Also, check the battery voltage and starting ampacity to make sure it's up to snuff. You would be surprised how much voltage all those low resistance connection points will drop, from the battery (source) to the load, and at the same time they tend to limit the current flow.

I replaced the thermister and all is better now.

 

[imgoin]

I had the same problem with the JD4600. The tractor would not start after being used for a couple of hours. I practically disassembled the tractor several times trying to locate the problem. The shut off solenoid was filling up with oil and not allowing the plunger to pull out. I would take the plunger and pump it a few times and the oil would squirt out, allowing it to function properly. I think a new solenoid was about $100. But, my thought was, if this went bad the next one will do the same. When the tractor wouldn't start, I would take the solenoid off and pump the oil out of it. Re install and it was good for 2-4 hours. Finally, one day I got tired of doing this, took the solenoid off, cut a little plate with a hole in it for a pto cable to go in, push the spot the solenoid is pushing and turn off the tractor.

This was done about 200 hours ago. Words of caution, the tractor will run with the key off and safety switches do not work. To turn off the tractor, I push in the red pto button.

 

[X13BRAVO]

My 4300 ran great all day shut it down . Next morning it turns over wont start JD service comes out tells me I need a new fuel shut off solenoid and puts one on.
runs good for 2 or 3 days then back to turning over but no start. I get on line find this page and start reading about this issue. The thermistor and figure I would try and replace it. Mine was behind the fuse box tucked inside the factory wire loom I had to really look for it you got to take the nuts off the fuse box and take your time to move it around till you can see behind it real tight spot. I got the part from JD for $6 put it on and now I can hear my solenoid make that click sound when I turn the key. I will post a picture of the thermistor after I spliced it in and put the heat wrap on it. My 4300 has been starting like new !!