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4300 hst fuel shut off UPGRADE?

8685 Views 39 Replies 7 Participants Last post by  DRK
have they come up with a fix for this issue? seems there is a plunger that retracts when you turn the key, to allow fuel flow. on my model tractor a 2000 4300 HST the device allows oil to get behind the plunger and cause a hydraulic BLOCK to the plunger retracting as it should.... sooo I have to remove the device from its very tight location and work the plunger to squeeze out all the oil, and then I reinstall the device... I had to make a custom socket to remove the two 10 mm bolt heads... hopeing some one has an update. On another note.... what is the down side of just removing this device, or cutting off the plunger rod so it cant ever block the fuel? is the fuel going to evaporate or run into the injectors or what???

thanks

Bob
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JD , ill add , that i plugged the new solenoid in to check its function(outside the fuel pump) and it is much snappier than the nold one... the old one retracts when there is no oil behind it, but it just does that...retracts... the new one SNAPS back
The solenoid on my 17 yr old 4610 (which still works well) measures 0.5 ohm from A to B (pull-in coil) and 23 ohm from A to C (hold-in coil).

The service manual for the 4610 provides the 0.4 ohm and 12.0 ohm specification values and says "If resistance does not meet specifications, replace fuel shutoff solenoid". That statement is pretty crazy given they don't provide any tolerance (e.g. 0.4 ohm +/- 0.2 ohm). I would bet that any solenoid pulled out of stock at the dealer will not measure exactly 0.4 ohm and 12.0 ohm.

That is good news that you say your new solenoid has a "snappier" pull in. Let's hope it works great.
hello JD Driver... the old solenoid measures 0.6 on A to B. and 11.5 on A to C. on my meter set at 200 ohms. The new Solenoid measures 0.7 on A to B, and measures 31.5 on A to C!!!!! whats that tell me???? i got a chinese solenoid?? when i get a non rainy day Ill start to pull the cowl off and might check the relays and thermistor
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hello JD, Driver, I got the new switch in and started the tractor up...but when i turned the key off, the tractors idle went down, but it didnt shut off. I had to throttle the idle lever to the minimum, to stall the tractor!..I have a video, but its MP4 and apparently thats not allowed here....dont know how to change it...
Hello @dvice,

What "new switch" are you referring to?
hello JD, Driver, I got the new switch in and started the tractor up...but when i turned the key off, the tractors idle went down, but it didnt shut off. I had to throttle the idle lever to the minimum, to stall the tractor!..I have a video, but its MP4 and apparently thats not allowed here....dont know how to change it...
the solenoid for the fuel shutoff.... not really a switch! the solenoid that Snapped back with authority........i guess i should have measured that it extended .500" when in the off position, before i installed it...
Is this a John Deere supplied M810324 fuel shutoff solenoid valve?

Like you, I would wonder if the plunger length of the newly installed solenoid valve is shorter in the off (extended) position than it should be. This might not totally shut off fuel to the fuel pump, and let the engine continue to run after turning the switch off.
i bought it on ebay from a guy selling a lot of john deere stuff, up in michigan..... it was $36, not $99! though........ the shut off is the extended position, the retract is the run position.... there isnt anything wrong with throttling down is there?.... I wonder now if the seat switch will still shut off the tractor.
The safety system on this tractor relies on being able to shutdown the engine at any throttle speed by removing power from the fuel shutoff solenoid, so it wouldn't be very safe to operate it without this feature.

When power is removed from the fuel shutoff solenoid, the actuator rod is forced out of the solenoid and into the pump by a spring. It sounds like the spring inside your solenoid valve may not be strong enough to overcome the force needed to completely shutoff fuel flow at the pump. I measured 4.8 lbs of spring force on an operational solenoid with a digital scale.
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I'm having the same problem I think. So I just picked up a 99 4500 and its not starting, it just cranks and cranks, so I pulled an injector line off to see if I was getting fuel an I was not. so that's when I found out about the fuel solenoid, so I replaced it with one from Deere, and its still not starting, is the solenoid supposed to pull in on its own or not? if i apply a tiny amount of pressure to it in works when I turn the key "wile out of tractor" put it back in and nothing. is it possible that the spring inside the injector pump is getting too week for it to work and I need a new injector? can someone sell me what I should be getting for volts or oms from the pull feed when I turn the key?
I'm having the same problem I think. So I just picked up a 99 4500 and its not starting, it just cranks and cranks, so I pulled an injector line off to see if I was getting fuel an I was not. so that's when I found out about the fuel solenoid, so I replaced it with one from Deere, and its still not starting, is the solenoid supposed to pull in on its own or not? if i apply a tiny amount of pressure to it in works when I turn the key "wile out of tractor" put it back in and nothing. is it possible that the spring inside the injector pump is getting too week for it to work and I need a new injector? can someone sell me what I should be getting for volts or oms from the pull feed when I turn the key?
The safety system on this tractor relies on being able to shutdown the engine at any throttle speed by removing power from the fuel shutoff solenoid, so it wouldn't be very safe to operate it without this feature.

When power is removed from the fuel shutoff solenoid, the actuator rod is forced out of the solenoid and into the pump by a spring. It sounds like the spring inside your solenoid valve may not be strong enough to overcome the force needed to completely shutoff fuel flow at the pump. I measured 4.8 lbs of spring force on an operational solenoid with a digital scale.
The fuel shutoff solenoid has a pull-in coil and a hold-in coil. The fact that applying a small amount of pressure to the plunger on the fuel shutoff solenoid with the key turned on is required for it to retract makes it possible that the pull-in coil is not being activated.

There are lots of threads discussing the fuel shutoff solenoid circuitry. You could start by replacing the K3 Fuel Shutoff relay, and if that doesn't fix it, you will probably need to replace the "thermistor".

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I'm having the same problem I think. So I just picked up a 99 4500 and its not starting, it just cranks and cranks, so I pulled an injector line off to see if I was getting fuel an I was not. so that's when I found out about the fuel solenoid, so I replaced it with one from Deere, and its still not starting, is the solenoid supposed to pull in on its own or not? if i apply a tiny amount of pressure to it in works when I turn the key "wile out of tractor" put it back in and nothing. is it possible that the spring inside the injector pump is getting too week for it to work and I need a new injector? can someone sell me what I should be getting for volts or oms from the pull feed when I turn the key?
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thank you Ill start there
The fuel shutoff solenoid has a pull-in coil and a hold-in coil. The fact that applying a small amount of pressure to the plunger on the fuel shutoff solenoid with the key turned on is required for it to retract makes it possible that the pull-in coil is not being activated.

There are lots of threads discussing the fuel shutoff solenoid circuitry. You could start by replacing the K3 Fuel Shutoff relay, and if that doesn't fix it, you will probably need to replace the "thermistor".

View attachment 798920
before I start tearing into the tractor where would I find the thermistor?
thank you Ill start there
It sounds to me like the solenoid has a non serviceable seal to prevent the oil from getting in it. I assume that seal is failing and causing the problem.

OOORR it might be that area of the pump isn't suppose to have oil present and something inside it is allowing oil to leak into an area it shouldn't be.

No amount of electricity is going to overcome a hydro locked piston or plunger. In the video provided a few posts back the guy depresses the plunger by hand and the oil clearly comes out around the shaft.

I doubt this particular problem is electrical.
He said he just replaced the fuel shutoff solenoid. Are you saying you think the new fuel shutoff solenoid has a bad seal????
It sounds to me like the solenoid has a non serviceable seal to prevent the oil from getting in it. I assume that seal is failing and causing the problem.
I was referring to the original OPs problem of the solenoid getting oil behind the plunger. Somewhere the discussion took a turn towards electrical. While that might cause the plunger not to get a proper signal the problem of oil preventing it from retracting is not electrical in my opinion.

It is probably more likely that area of the injection pump is sealed from the oil supply and that seal is allowing oil to get to the solenoid.
He said he just replaced the fuel shutoff solenoid. Are you saying you think the new fuel shutoff solenoid has a bad seal????
I totally agree that this could be a mechanical problem, not an electrical problem, but since @xjustchrisx just replaced the fuel shutoff solenoid, it seemed less likely in this case to be a plunger hydraulic lock issue which is why I recommended first starting with the PTC (called a thermistor) and relay. Most of us with these older tractors have a fuel solenoid shutoff relay on the shelf because we have had one fail - including me on my 4610, and that same relay is used in multiple areas.

It is unfortunate that the O.P. never came back to tell us what finally fixed his 4300!
I was referring to the original OPs problem of the solenoid getting oil behind the plunger. Somewhere the discussion took a turn towards electrical. While that might cause the plunger not to get a proper signal the problem of oil preventing it from retracting is not electrical in my opinion.

It is probably more likely that area of the injection pump is sealed from the oil supply and that seal is allowing oil to get to the solenoid.
Not sure since my 4610 does not use this part, but maybe someone who has replaced one on a 4500 or other 4X00 tractor will respond.

You can pull the relay and test it with a multi-meter first before replacing if you like. Power initially flows through relay pin 30 to pin 87A and then to the PTC (thermistor). After the PTC warms and opens, the K3 relay energizes and switches the relay wiper to pin 87 to open the pull-in coil circuit (and reset the PTC). If the un-energized K3 relay has low resistance between terminals 30 and 87A, it should be fine to activate the pull-in coil (if the PTC (thermistor) is good).

You can also energize the relay by applying 12 Vdc across relay terminals 85 and 86 (polarity not important), and make sure that there is no longer continuity between relay terminals 30 and 87A.
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before I start tearing into the tractor where would I find the thermistor?
Not sure since my 4610 does not use this part, but maybe someone who has replaced one on a 4500 or other 4X00 tractor will respond.

You can pull the relay and test it with a multi-meter first before replacing if you like. Power initially flows through relay pin 30 to pin 87A and then to the PTC (thermistor). After the PTC warms and opens, the K3 relay energizes and switches the relay wiper to pin 87 to open the pull-in coil circuit (and reset the PTC). If the un-energized K3 relay has low resistance between terminals 30 and 87A, it should be fine to activate the pull-in coil (if the PTC (thermistor) is good).

You can also energize the relay by applying 12 Vdc across relay terminals 85 and 86 (polarity not important), and make sure that there is no longer continuity between relay terminals 30 and 87A.
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View attachment 798939
Having the same exact problem with my 4610. Oil gets behind it and will not start. Pull it off with a 1/4 in ratchet with an extension and a 10mm socket. Pump it a few times to clear the oil and I am back up and running for a few days. About a year ago I replaced it with a JD part from the dealer and it was great for a while. Now this one started the same thing. I also know someone that is having the same issue with a 4300. This appears to be a known problem with no way to fix it. It kinda sucks when you are in snow and have to fix the silly thing.
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