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Kubota G1800 won't shut off
#1
M
mrficxit
M
mrficxit
Hello all,
I'm a new member to LMF and thank you all in advance for your advice and help. I'm sorry this is such a long post but I want you all to know what I have done, what I think might need to be done, and questions I have. I have read as much as I can on my issue online, read through the various threads on LMF and have even been able to download an electrical schematic. But my problem still persists.
I have a G1800 riding mower that starts just fine, runs just fine, but won't shut off when I turn the key to the off position.
Things I have tried:
1. Verified that the engine stop solenoid (ESS) works just fine. Direct connected to battery and it engages just fine and stops the engine.
2. Took loose the two ground wires next to the ESS, cleaned them and reattached.
3. Verified the battery is at full charge.
4. Removed the screen under the instrument panel, found three fuses. The fuse connector was very dirty. I cleaned the contacts thoroughly, replaced the 10, 15, and 20 amp fuses.
5. I have put a test meter on the connector that is right before the ESS and do not get any voltage readings when I turn the key to the off position.
Based upon my research, there are 3 items left to check: the combination box, the ignition switch and fusable links. Here is what I know (realizing there is a LOT I don't know).
Combination box: There are some posts where folks have discussed replacing this item (and it didn't fix their problem, and this part is quite expensive). I don't have any idea how this item could be replaced??? Is there a way to test to see if this "magic" box is working? It was very dirty but I have cleaned it. It is cracked in several places, but I have read that others have also been cracked and they still worked. All the wires seem to be in good shape. If it does turn out to be bad, how would I go about replacing this item?
Ignition Switch:Some have mentioned testing to see if it is sending a signal to the ESS when turned to the off position so the ESS can do it's job. How would I test this switch?
Fusable Links:I don't find any fusable links. Based upon the schematic I have, there is supposed to be one over by the starter. I don't see one but I'm sure it is there. Would this fusable link cause the ESS to not engage? It looks like it is for a starting problem, which is not my problem...but that could be my ignorance.
Are there other things that I have not read about trying that you all would suggest? I am interested in all ideas. I really don't like having to open the hood to manually shut this thing off. I am toying with the idea of adding a stop button, but really don't know how to do this...and it is really not what I want to do, but will if I can't figure this out.
Thanks again in advance for all your help.
Del
I'm a new member to LMF and thank you all in advance for your advice and help. I'm sorry this is such a long post but I want you all to know what I have done, what I think might need to be done, and questions I have. I have read as much as I can on my issue online, read through the various threads on LMF and have even been able to download an electrical schematic. But my problem still persists.
I have a G1800 riding mower that starts just fine, runs just fine, but won't shut off when I turn the key to the off position.
Things I have tried:
1. Verified that the engine stop solenoid (ESS) works just fine. Direct connected to battery and it engages just fine and stops the engine.
2. Took loose the two ground wires next to the ESS, cleaned them and reattached.
3. Verified the battery is at full charge.
4. Removed the screen under the instrument panel, found three fuses. The fuse connector was very dirty. I cleaned the contacts thoroughly, replaced the 10, 15, and 20 amp fuses.
5. I have put a test meter on the connector that is right before the ESS and do not get any voltage readings when I turn the key to the off position.
Based upon my research, there are 3 items left to check: the combination box, the ignition switch and fusable links. Here is what I know (realizing there is a LOT I don't know).
Combination box: There are some posts where folks have discussed replacing this item (and it didn't fix their problem, and this part is quite expensive). I don't have any idea how this item could be replaced??? Is there a way to test to see if this "magic" box is working? It was very dirty but I have cleaned it. It is cracked in several places, but I have read that others have also been cracked and they still worked. All the wires seem to be in good shape. If it does turn out to be bad, how would I go about replacing this item?
Ignition Switch:Some have mentioned testing to see if it is sending a signal to the ESS when turned to the off position so the ESS can do it's job. How would I test this switch?
Fusable Links:I don't find any fusable links. Based upon the schematic I have, there is supposed to be one over by the starter. I don't see one but I'm sure it is there. Would this fusable link cause the ESS to not engage? It looks like it is for a starting problem, which is not my problem...but that could be my ignorance.
Are there other things that I have not read about trying that you all would suggest? I am interested in all ideas. I really don't like having to open the hood to manually shut this thing off. I am toying with the idea of adding a stop button, but really don't know how to do this...and it is really not what I want to do, but will if I can't figure this out.
Thanks again in advance for all your help.
Del
#3
reddragon
reddragon
#5
reddragon
reddragon
#7
reddragon
reddragon
#8
reddragon
reddragon
#11
reddragon
reddragon
#14
reddragon
reddragon
#15
reddragon
reddragon
#17
reddragon
reddragon
#19
reddragon
reddragon
#20
reddragon
reddragon
#21
reddragon
reddragon
#23
M
mrficxit
M
mrficxit
Going to go to the local Kubota dealer and see if I can get a better electrical diagram. Guess I will take the time to pull wires and see if I can find a broken, rubbed, shorted, etc. wire...just didn't really want to do it but oh well. KennyV and reddragon - I really should just put in a separate kill switch. It would be easier and cleaner, but I'm just twisted that way. :laughing: I plan to start at the connector right before the shut off solenoid and work backwards.
reddragon - thanks for taking the time to call the kubota mechanic. I really do appreciate that. It does make me feel somewhat better that it's a pretty common thing to go bad. Like you also said, it doesn't make me feel better that Kubota would put their electrical components in such a "mystery" box. I really should take the advice to put in a separate switch! And I just may do that.
djrussell - I just can't see how I could break into that box without really messing things up. If you look at the pic, you can see that the material surrounding all the connections, wires, etc. is a molded epoxy type material. Not sure exactly how that would work. However, if I come to the conclusion to bite the bullet and get a new combo box, I may just go for it and see what happens.
Thanks for all your advice guys. I'll let you know what I find out. If you have any other thoughts, please keep the posts coming.
reddragon - thanks for taking the time to call the kubota mechanic. I really do appreciate that. It does make me feel somewhat better that it's a pretty common thing to go bad. Like you also said, it doesn't make me feel better that Kubota would put their electrical components in such a "mystery" box.
I really should take the advice to put in a separate switch! And I just may do that.djrussell - I just can't see how I could break into that box without really messing things up. If you look at the pic, you can see that the material surrounding all the connections, wires, etc. is a molded epoxy type material. Not sure exactly how that would work. However, if I come to the conclusion to bite the bullet and get a new combo box, I may just go for it and see what happens.
Thanks for all your advice guys. I'll let you know what I find out. If you have any other thoughts, please keep the posts coming.
#24
M
mrficxit
M
mrficxit
Went to local Kubota dealer and spoke to parts person as well as the service manager. Found out the combo box is $155 + tax (OUCH :frown. Hope to find it cheaper online. Does anybody have recommendations for a reliable parts place online?
Service manager stated the combo box was probably the culprit. Stated the relay that powers the ESS is indeed in the combo box. Also told me that in order to replace the combo box, need to unwrap the electrical bundle to the first connector (behind the radiator screen), disconnect the old, connect the new and hope that solves the problem.
Before I do that I plan to purchase a 12V DC test light and see if I can trace any voltage out of the combo box to the ESS. However, as another test I tried to see if any of the safety switches would shut down the mower. I have not disabled any safety switch. I was able to start the mower without sitting in the seat. I then tried to start the blades on the mower deck (still not sitting on the seat) and the blades started turning just fine and the mower just kept running. That should have shut down the mower right? I wonder if the relay in the combo box also affects these safety switches where they won't work? Does this test mean anything?
. Hope to find it cheaper online. Does anybody have recommendations for a reliable parts place online?Service manager stated the combo box was probably the culprit. Stated the relay that powers the ESS is indeed in the combo box. Also told me that in order to replace the combo box, need to unwrap the electrical bundle to the first connector (behind the radiator screen), disconnect the old, connect the new and hope that solves the problem.
Before I do that I plan to purchase a 12V DC test light and see if I can trace any voltage out of the combo box to the ESS. However, as another test I tried to see if any of the safety switches would shut down the mower. I have not disabled any safety switch. I was able to start the mower without sitting in the seat. I then tried to start the blades on the mower deck (still not sitting on the seat) and the blades started turning just fine and the mower just kept running. That should have shut down the mower right? I wonder if the relay in the combo box also affects these safety switches where they won't work? Does this test mean anything?
#25
reddragon
reddragon
#27
reddragon
reddragon
#28
D
djrussell
I understand the pic now. I didn't see that on first glance. Since you're headed down the replacement path anyway, you could try to disolve the sealant or cut it away. I'm not sure what material you've got there but there are chemicals that will eat it. I've heard that gas can dissolve silicone. I remember some capacitors would get an epoxy coating that may be different though.
It's really stupid that the connection to this box is so far away. That's bad design IMO. If you're lucky you may find a connection under the sealant and the wires won't be soldered to the board.
D
djrussell
I understand the pic now. I didn't see that on first glance. Since you're headed down the replacement path anyway, you could try to disolve the sealant or cut it away. I'm not sure what material you've got there but there are chemicals that will eat it. I've heard that gas can dissolve silicone. I remember some capacitors would get an epoxy coating that may be different though.
It's really stupid that the connection to this box is so far away. That's bad design IMO. If you're lucky you may find a connection under the sealant and the wires won't be soldered to the board.
#29
reddragon
reddragon
#33
reddragon
reddragon
#34
G
goodolboydws
G
goodolboydws
goodolboydws....
Well, Kenny, I bow to your superior knowledge of Kubotas.
And if Kubotas (this one in particular) leave the rack solenoid for the FI pumps in the on position with the result that the path of additional fuel to the pump is uninterrupted all the time that their engines are off, that's another story. I'd thought that someone must have made a typo in the thread and had read it as actually being the other way.
Typically the gold standard for safety would have a fuel control solenoid always be in the UN-energized position disconnecting the fuel supply whenever the ignition switch is off and the the engine isn't supposed to be running. Yes the relay would tend need to be heavier to last as long if it's wired in such a way that it's conducting power all the time that an engine's running, and more prone to eventual failure for that reason, BUT it would be safer to have an engine that doesn't start than one that doesn't stop...... Sounds like a rather poor design choice from a safety standpoint.
That accessory shut off cable sounds good-I'd forgotten to add it to my list... I'd think of it as an "improvement" rather than a "workaround" though. (One less thing on-board to fail electrically.
And you're right I suppose for someone who's heavyhanded, grinding instead of using a purpose-designed cutting wheel in a Dremel type tool properly could potentially cause vibration induced damage.
As I said earlier, I'm glad my 42 year young Ford 2000 diesel doesn't depend on any electrics to control it's fuel flow to the pump (either on or off).
Sometimes an elegant soution (elegent in it's engineering sense=simpler) shouldn't necessarily be abandoned, in this case it's apparently being done because Kubota or the Federal powers higher up the food chain thought enough people would be too dumb to be able to remember to simply pull a cable to the on/start/run position when starting the engine and then return it to to off position later and then back on again the next time. (That wouldn't surprise me seeing how the newer cars require less and less attention or input from drivers every year, and those vehicles have fewer and fewer serviceable parts too, many things now needing to be replaced rather than being maintained-which reflects on the apparent perception of the quality of available mechanics too.)
Does Kubota actually use a full submergence type internal potting of all of the individual components within the control module itself, or is this module's body/case only hermetically sealed with an external epoxy coating to protect it from external introduction of water and other environmental contamination? From the "several cracks" comment that the original poster had made, full encapsulization doesn't sound as likely.
For those who haven't heard this before:
For heat transfer purposes a module often has either it's own heat sink being a part of the case or is attached via a relatively large contact area connection to an external metal heat sink surface, and between which surfaces is sometimes used a dielectric grease to ensure good contact, (this was commonly done with automotive ignition control modules for one example, and the engine compartment mounted modules tend to fail early if the grease layer was left or forceably washed out-can you say "careless use of a pressure washer"?).
When the primary concern is dampening vibration, modules often use either a semi-free suspension of components with cushioning (perhaps taped to wires in a wire harness) rather than having them be attached directly to a rigid piece subject to heavy vibration, or by using some sort of rubber-type isolation if being directly attached to a solid surface subject to such vibration.
Potting individual electronic or electrical components within a matrix of any solid, fairly non-resiliant material such as most epoxy recipies does very little if anything to dampen internal vibration of individual components to any significant degree-other than to possibly help retain the components themselves to a circuit board or internal connector. And doing this increases the possibility of causing a different problem
There are other materials available, but when using epoxy as a potting material it's most typically used as an insulator rather than a conductor, so it would more often than not tend to trap heat in the area immediately surrounding each individual component-with no way to disperse that heat, which would tend to magnify any overheating problem limited to a single component-or to everything inside the module's case for that matter. If overheating is not an issue for any of the components, (and especially if there is no relay/solenoid inside) full encapsulization might make more sense.
Modules are typically sealed externally or internallly, seldom both-but typically for different reasons.
thanks
#37
G
goodolboydws
Thanks Kenny, I learned something today and it isn't even noon.
So, they really do leave the fuel supply uninterrupted while the machine's power is off. Interesting.
I'd missed the photos, but now from what appears to be rust that I saw, it would seem that rain or cleaning water or just too much condensation is getting to this control's location and that it probably takes too long to dry out passively when the machine is not being used, so the partial encapsulization appears to make sense, while leaving the majority of the individual component bodies exposed to what may well be an inadequate air flow path. (maybe add a spacer washer at each mounting lug if/when that module gets replaced?)
I'd also examine the connector VERY closely under magnification to check for oxidation or simple looseness and evidence of possible internal arcing on one or more of the pin/socket pairs. (and if water is getting to and infiltrating that connector that could help explain someone's reference to a tech's comment about this module needing replacement often.) After seeing that apparent rust, I'd be concerned that water might be getting to and/or staying too long at other electrical component locations as well.... and inspect all connectors and leave them with a generous coating of dielectric grease inside to keep moisture out.
As to it being impractical to de-pot something, when you get right down to it, a lot of what we tinkerers/fixers/experimenters/re-designers do is impractical-at least in terms of OUR labor time involved in doing it. Doesn't your "personal" solution fall into that category-and run somewhat counter to your earlier advise on why to replace the module? I believe that one of the things that the original poster had expressed concern for was the cost of the replacement part-but he doesn't seem to be averse to spending time on the project.
G
goodolboydws
-------------------------
Thanks Kenny, I learned something today and it isn't even noon.
So, they really do leave the fuel supply uninterrupted while the machine's power is off. Interesting.
I'd missed the photos, but now from what appears to be rust that I saw, it would seem that rain or cleaning water or just too much condensation is getting to this control's location and that it probably takes too long to dry out passively when the machine is not being used, so the partial encapsulization appears to make sense, while leaving the majority of the individual component bodies exposed to what may well be an inadequate air flow path. (maybe add a spacer washer at each mounting lug if/when that module gets replaced?)
I'd also examine the connector VERY closely under magnification to check for oxidation or simple looseness and evidence of possible internal arcing on one or more of the pin/socket pairs. (and if water is getting to and infiltrating that connector that could help explain someone's reference to a tech's comment about this module needing replacement often.) After seeing that apparent rust, I'd be concerned that water might be getting to and/or staying too long at other electrical component locations as well.... and inspect all connectors and leave them with a generous coating of dielectric grease inside to keep moisture out.
As to it being impractical to de-pot something, when you get right down to it, a lot of what we tinkerers/fixers/experimenters/re-designers do is impractical-at least in terms of OUR labor time involved in doing it. Doesn't your "personal" solution fall into that category-and run somewhat counter to your earlier advise on why to replace the module?
I believe that one of the things that the original poster had expressed concern for was the cost of the replacement part-but he doesn't seem to be averse to spending time on the project.
#41
M
mrficxit
M
mrficxit
Well guys, it's been a while since I first posted about my problem with my Kubota mower. I decided to be proactive (very unusual for me :laughing and fix my problem before the new mowing season was upon me.
I was going to use KennyV's suggestion and put in a push button, inline fused, wire to actuate the shut off solenoid. I was looking for a "convenient" spot to drill a hole for the push button when I happened to see a place on the left side of the mower where there was a "bulge" in the body of the mower. There was a grommet covering a hole that was already there. As I looked closer, I could tell that this spot was directly in line with the shut off solenoid.
I then realized I could buy a choke cable and modify it to manually pull on the shut off solenoid (which has a vertical screw sticking up on the bracket) and kill the engine without having to open the hood every time...and it was much easier (in my opinion) than wiring in a fused wire. So I went to my local hardware store and bought a 5' choke cable ($11), fitted it through the hole, measured what I needed, and cut off the excess.
I think I have read in some other forums where some Kubota machines are still outfitted with a shut off cable. Maybe they were on the G1800's at one time??? I realize that I can still leave the key on and shut off the mower, thereby draining my battery. I will just have to watch out for that.
Here are some pics.
and fix my problem before the new mowing season was upon me.I was going to use KennyV's suggestion and put in a push button, inline fused, wire to actuate the shut off solenoid. I was looking for a "convenient" spot to drill a hole for the push button when I happened to see a place on the left side of the mower where there was a "bulge" in the body of the mower. There was a grommet covering a hole that was already there. As I looked closer, I could tell that this spot was directly in line with the shut off solenoid.
I then realized I could buy a choke cable and modify it to manually pull on the shut off solenoid (which has a vertical screw sticking up on the bracket) and kill the engine without having to open the hood every time...and it was much easier (in my opinion) than wiring in a fused wire. So I went to my local hardware store and bought a 5' choke cable ($11), fitted it through the hole, measured what I needed, and cut off the excess.
I think I have read in some other forums where some Kubota machines are still outfitted with a shut off cable. Maybe they were on the G1800's at one time??? I realize that I can still leave the key on and shut off the mower, thereby draining my battery. I will just have to watch out for that.
Here are some pics.