Kubota BX23S runs until it sputters and dies

[JohnR in VA]

My Kubota BX23S runs until it sputters and dies.

After investigating several potential causes, I let the tractor sit for a day or so, and it started fine, sputtering out again after about 15-20 minutes.

I thought some debris had entered the tank blocking the fuel line. My theory was that after a while, the fuel could seep past the blockage, allowing operation until the fuel rate demand become too high.

I drained the fuel and blew the lines with a compressor. I reassembled, and it ran like a champ for a few months.

Later in the summer, the same issue recurred. Thinking I must've allowed some debris to enter the tank again, I blew the lines again. Problem solved... until 2-3 months later. Same behavior, same repair. Runs like a champ--going through several tanks refills--for a few months.

Is there a filter in the tank at the fuel line that might have come dislodged? Or something else that I'm missing?

Welcome any advice...
-JohnR in VA

 

[lynnmor]

My Kubota BX23S runs until it sputters and dies.

After investigating several potential causes, I let the tractor sit for a day or so, and it started fine, sputtering out again after about 15-20 minutes.

I thought some debris had entered the tank blocking the fuel line. My theory was that after a while, the fuel could seep past the blockage, allowing operation until the fuel rate demand become too high.

I drained the fuel and blew the lines with a compressor. I reassembled, and it ran like a champ for a few months.

Later in the summer, the same issue recurred. Thinking I must've allowed some debris to enter the tank again, I blew the lines again. Problem solved... until 2-3 months later. Same behavior, same repair. Runs like a champ--going through several tanks refills--for a few months.

Is there a filter in the tank at the fuel line that might have come dislodged? Or something else that I'm missing?

Welcome any advice...
-JohnR in VA

Check that the tank is vented, possibly in the fuel cap. When it happens again, open the cap and listen for air going in.

 

[Roadworthy]

It is also possible you DO have some debris or algae in the tank and it's taking a couple of months to form back at the fuel outlet of the tank. There may be a filter screen of some sort there to prevent the crud from getting further into your fuel system. Blowing air back through the fuel lines may only be clearing it until it can form again. I don't know how the fuel output of your tank works so that's just my guess based on problems I'm experiencing with my F100 pickup truck.

 

[Russell King]

Is your fuel tank plastic or metal? If plastic it is more likely an algae problem. If metal it could be a rust in the tank problem.
But you never said you changed the filter or filters. Find out how many fuel filters and replace all of them and treat your fuel with algaecide afterwards. If that doesn’t fix it then come back for more suggestions.

 

[Henro]

Is your fuel tank plastic or metal? If plastic it is more likely an algae problem. If metal it could be a rust in the tank problem.
But you never said you changed the filter or filters. Find out how many fuel filters and replace all of them and treat your fuel with algaecide afterwards. If that doesn’t fix it then come back for more suggestions.

Changing the fuel filters is a good idea. I believe there are two on your BX.

In your case the search function is your friend here. I remember at least one other thread that had the exact same issue that you are experiencing, and it turned out to be a piece of plastic floating around in the tank that blocked the outlet randomly.

If you find other threads related to similar issues on a BX, you may find some ideas that are helpful in addition to what has been said above.

 

[GreensvilleJay]

No filter in the tank and unless you REMOVE the tank, blowing air will NOT get out the culprit.... After I limped home, I spent the time(yeah..it's kinda involved 'proceedure' to remove the tank) and flushed out a 'chunk' of plastic about size of a pencil eraser. NO way blowing air got it out( 3 chamered tank) ,flushing with water several times got it out. I spent a huge amount ($1.25) and bought a sink filter screen, spent 5 minutes making it fit better, intot he fuel tank filler neck.Got 100+hrs on it , zero problems.

 

[JohnR in VA]

Check that the tank is vented, possibly in the fuel cap. When it happens again, open the cap and listen for air going in.

Thanks for this response, Lynnmor. I opened the cap and listened for air entering the tank, but didn't hear anything. The background hum from cicadas didn't help. So I cleaned the cap, and periodically partially opened the cap while driving to vent the tank. Th tractor exhibited the same behavior.

When it stalls, I just walk away and let it sit for a while. If I let it sit for 20-min or so, I can usually get another 20-30 min out of it.

 

[JohnR in VA]

Is your fuel tank plastic or metal? If plastic it is more likely an algae problem. If metal it could be a rust in the tank problem.
But you never said you changed the filter or filters. Find out how many fuel filters and replace all of them and treat your fuel with algaecide afterwards. If that doesn’t fix it then come back for more suggestions.

I appreciate the response Russell. I have replaced the fuel filters (2) once on schedule. I'll replace them again. It'll be ahead of schedule, but that's not a big deal at all. I've tried SeaFoam, but maybe I'll also try some algaecide.

 

[JohnR in VA]

It is also possible you DO have some debris or algae in the tank and it's taking a couple of months to form back at the fuel outlet of the tank. There may be a filter screen of some sort there to prevent the crud from getting further into your fuel system. Blowing air back through the fuel lines may only be clearing it until it can form again. I don't know how the fuel output of your tank works so that's just my guess based on problems I'm experiencing with my F100 pickup truck.

No filter in the tank and unless you REMOVE the tank, blowing air will NOT get out the culprit.... After I limped home, I spent the time(yeah..it's kinda involved 'proceedure' to remove the tank) and flushed out a 'chunk' of plastic about size of a pencil eraser. NO way blowing air got it out( 3 chamered tank) ,flushing with water several times got it out. I spent a huge amount ($1.25) and bought a sink filter screen, spent 5 minutes making it fit better, intot he fuel tank filler neck.Got 100+hrs on it , zero problems.

Thanks for these inputs. I''ll remove the tank. clean it with algaecide, and replace the filters. I can probably do that without the shop manual, but maybe it's time to buy it. Not sure why the manuals are so expensive. Years back, I bought a Haynes shop manual for an old Toyota Corolla--for about $20-- and fixed 100 items over the years. It was well worth the investment, maybe this will be also.

 

[JohnR in VA]

Thanks for these inputs. I''ll remove the tank. clean it with algaecide, and replace the filters. I can probably do that without the shop manual, but maybe it's time to buy it. Not sure why the manuals are so expensive. Years back, I bought a Haynes shop manual for an old Toyota Corolla--for about $20-- and fixed 100 items over the years. It was well worth the investment, maybe this will be also.

Sorry for the delayed response - I didn't buy the shop manual, but I went through the process of removing the tank anyway, taking several pictures along the way to ensure I could get it back together. When the tank was completely removed, I could hear something sizable rattling inside

, so I moved the tank around to work the object toward the opening.

What I found astonished me. It was a nozzle and screw cap from a fuel can. Apparently my daughter's (now ex) boyfriend was refueling the tractor last year when he lost control of the tank and broke off the nozzle from the can and into the kubota fuel tank. He told my daughter and when they couldn't get it out, they conspired not to tell the old man (me). Yep, Dad ain't happy about that.

Nonetheless, I removed the "debris", cleaned the tank, reassembled everything, and it's running fine now. I appreciate the advice you gave me, and I'll get back into the forum to learn more.

 

[GreensvilleJay]

WOW, that's a BIG chunk of 'problem' ! Mine was 'just' a sliver or chard of plastic 'donut'. I broke a knob off(all the rest slide off...),hope you have help putting seat assy back on...dang heavy and awkward...
reminds me I should put the 'remote' fuel fitler/stopcock on one day.....
There is a WSM online,free to download.

 

[Henro]

WOW, that's a BIG chunk of 'problem' ! Mine was 'just' a sliver or chard of plastic 'donut'. I broke a knob off(all the rest slide off...),hope you have help putting seat assy back on...dang heavy and awkward...
reminds me I should put the 'remote' fuel fitler/stopcock on one day.....
There is a WSM online,free to download.

This link should work for the workshop manual, hopefully:

Index of Kubotabooks/Tractor Owners Manuals/

Click on the BX23S WSM.

If I remember correctly the electrical wiring diagrams are poor, but the rest of the manual is excellent.

 

[The Bald Eagle]

Thanks for the tip! Pulled my tank today on my BX25D. Found a bunch of small debris inside, and also, the 90 degree elbow fitting coming out of the bottom of the tank was corroded and clogged with gunk. the diameter was severely restricted. Could not find a part number from the dealer, it might be considered part of the tank. So I used a Dremel and wire brush bit and cleaned it out. Tractor ran like a champ after reassembly!

 

[Drypc]

My Kubota BX23S runs until it sputters and dies.

After investigating several potential causes, I let the tractor sit for a day or so, and it started fine, sputtering out again after about 15-20 minutes.

I thought some debris had entered the tank blocking the fuel line. My theory was that after a while, the fuel could seep past the blockage, allowing operation until the fuel rate demand become too high.

I drained the fuel and blew the lines with a compressor. I reassembled, and it ran like a champ for a few months.

Later in the summer, the same issue recurred. Thinking I must've allowed some debris to enter the tank again, I blew the lines again. Problem solved... until 2-3 months later. Same behavior, same repair. Runs like a champ--going through several tanks refills--for a few months.

Is there a filter in the tank at the fuel line that might have come dislodged? Or something else that I'm missing?

Welcome any advice...
-JohnR in VA

I’ve got the same problem you have and have followed everyone’s recommendations. I’ve been a mechanic myself professionally for over 35 years and this one has had me stumped as well. I’ve noticed that when I first fire up the tractor it runs Awsome for an hour or so, or until I hit a hill or hit a bump and come off the seat momentarily. I’ve also noticed that if I shut it down let it sit for 15 to 20 min it fires up and runs great as if a reset button has been hit. I went looking in the safety portion of the electrical circuit and found there is a OPC timer which is attached to seat.
The OPC timer, operator presence control works with the safety switch like the neutral switch, PTO switch, and particularly the seat switch. When you come off the seat this breaks an electrical circuit in the seat switch which tells the OPC timer and relay. Since drivers often reposition, lean forward, hit bumps. Each break in the contacts from loss of seat pressure would kill the engine. So there is a timer that delays that signal a couple of seconds before the engine shuts off. That is what the OPC does. It slows down the kill signal for the safety switch. So it’s possible if this timer is bad this in fact could be the issue I’m having, and not so much as a fuel issue that naturally everyone gravitates towards. So I’m ordering this opc timer once I verify the unit is bad by
The OPC timer, operator presence control works with the safety switch like the neutral switch, PTO switch, and particularly the seat switch. When you come off the seat this breaks an electrical circuit in the seat switch which tells the OPC timer and relay. Since drivers often reposition, lean forward, hit bumps. Each break in the contacts from loss of seat pressure would kill the engine. So there is a timer that delays that signal a couple of seconds before the engine shuts off. That is what the OPC does. It slows down the kill signal for the safety switch. The OPC timer, operator presence control works with the safety switch like the neutral switch, PTO switch, and particularly the seat switch. When you come off the seat this breaks an electrical circuit in the seat switch which tells the OPC timer and relay. Since drivers often reposition, lean forward, hit bumps. Each break in the contacts from loss of seat pressure would kill the engine. So there is a timer that delays that signal a couple of seconds before the engine shuts off. That is what the OPC does. It slows down the kill signal for the safety switch.

 

[GreensvilleJay]

post #14 above seems like SPAM to me.....

 

[cthomas]

Some members install a tea filter into the neck of the fuel tank to prevent debris from entering tank. This one has good and somewhat funny reviews.

https://www.amazon.com/gp/product/B01M0TPLNG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

 

[Drypc]

I’ve got the same problem you have and have followed everyone’s recommendations. I’ve been a mechanic myself professionally for over 35 years and this one has had me stumped as well. I’ve noticed that when I first fire up the tractor it runs Awsome for an hour or so, or until I hit a hill or hit a bump and come off the seat momentarily. I’ve also noticed that if I shut it down let it sit for 15 to 20 min it fires up and runs great as if a reset button has been hit. I went looking in the safety portion of the electrical circuit and found there is a OPC timer which is attached to seat.
The OPC timer, operator presence control works with the safety switch like the neutral switch, PTO switch, and particularly the seat switch. When you come off the seat this breaks an electrical circuit in the seat switch which tells the OPC timer and relay. Since drivers often reposition, lean forward, hit bumps. Each break in the contacts from loss of seat pressure would kill the engine. So there is a timer that delays that signal a couple of seconds before the engine shuts off. That is what the OPC does. It slows down the kill signal for the safety switch. So it’s possible if this timer is bad this in fact could be the issue I’m having, and not so much as a fuel issue that naturally everyone gravitates towards. So I’m ordering this opc timer once I verify the unit is bad by
The OPC timer, operator presence control works with the safety switch like the neutral switch, PTO switch, and particularly the seat switch. When you come off the seat this breaks an electrical circuit in the seat switch which tells the OPC timer and relay. Since drivers often reposition, lean forward, hit bumps. Each break in the contacts from loss of seat pressure would kill the engine. So there is a timer that delays that signal a couple of seconds before the engine shuts off. That is what the OPC does. It slows down the kill signal for the safety switch. The OPC timer, operator presence control works with the safety switch like the neutral switch, PTO switch, and particularly the seat switch. When you come off the seat this breaks an electrical circuit in the seat switch which tells the OPC timer and relay. Since drivers often reposition, lean forward, hit bumps. Each break in the contacts from loss of seat pressure would kill the engine. So there is a timer that delays that signal a couple of seconds before the engine shuts off. That is what the OPC does. It slows down the kill signal for the safety switch.

post #14 above seems like SPAM to me.....

 

[Drypc]

post #14 above seems like SPAM to me.....

Nope not spam just hours of trouble shooting, I’m the only person who puts fuel in my tractor so I know debris of any kind doesn’t make it into the tank. I’ve tried all of the recommended above and currently have my tractor skirts raised ready to be pulled to go through each fitting I’ve drained the tank put cameras down into the tank searching and nothing so before I finish tearing this machine down I’m going to invest in this timer if I’m wrong nothing new if I’m right I’ve helped several people that’s all so no spam here just trying to help. I did say I was a mechanic but I’m also a retired electrical engineer.

 

[GreensvilleJay]

When my BX23S did the 'shuttering and die', the culprit was a tiny sliver of black plastic IN the outlet spigot of the tank. After a week of random runs great then die, I removed the tank and properly cleaning it. After that , installed a sink strainer in the fuel neck(others use cold press mason jar SS filter ). Over 800 hrs since then ZERO fuel issues.

A faulty OPC won't 'sputter and die', it's quite a quick turn off. Easy to test, simply press peddle a bit forward and get off seat or stand next to tractor move treadle peddle. Engine dies in 2 seconds,+-. Doing it several times ,the way it shuts down is always the same. You can bench test it with a scope and battery of course.

Shuttering tends to be a random length events and not repeatable. Engine will run rough then stop after say 10 seconds, 2 second, 4 seconds NEVER a consistent 2 seconds.

 

[sitric]

Not sure why anyone would think his posts are spam. Well thought out approach to fixing a problem, with a promise to follow up with results.