jgoodma1
Bronze Member
Hi. I'm a total rookie with diesel maintenance and problem diagnosis. I have a Kubota L48 backhoe I bought used a few years ago with around 1000 hours on it, and I put maybe 50 hours on it per year. For the past 6 months, it has been having a sporadic problem with the motor suddenly dying when it's been idling for 10 minutes, or so. Usually when I'd turn off the key and then turn it on again, and I would not hear the fuel solenoid click and sure enough, it would crank but not start. Then on maybe the third or fourth try, I'd hear the solenoid click and sure enough, it would start back up again. I might not have the problem again all day.
Now, my L48 is starting only occasionally. The problem has become worse over the last month, and now it almost never starts. I can clearly hear the stop solenoid click when it is working, and the motor starts right up. In the past, the motor would sometimes not start.....and there was no solenoid click.....and I'd let it sit 5 minutes and it would start and run all day. Now, if it starts, it may run for a couple of hours or it may die right in the middle of going up the driveway. And then, it will not start no matter how long I let it sit. A few days ago, I bought a new stop solenoid and installed it. I turned the key, heard the click, and it started right up. I turned it off 15 minutes later, and tried to restart it and there was no click and no start. 5 minutes later it clicked and started and ran the rest of the day, so I thought maybe I just had not turned the key all the way or something. Then the next day, it started right up, and I drove it 200 feet up my driveway and it died in the middle of the driveway. I had no way to move it and we could not go around it. I took the old solenoid, and sawed off the fuel stop rod, and took the new solenoid out and reinstalled the old one, and the motor started right up, so I know for certain that the solenoid is not actuating the stop rod. I now was able to move the machine. I was picking up debris along my driveway, so I kept the machine on the driveway and kept it running for several hours. I killed it by removing the air filters and blocking off the air intake with some folded up heavy-duty trash bags.
That's where I am now. I'm a rookie mechanic and electrical problems give me fits. I have the workshop manual, but I can't decipher everything in the schematic. In the manual, it says if the motor cranks but doesn't start, that the problem is the solenoid. Oh, and I also have a 1-year old key switch and I removed that and it looks brand new. Plus, all the electrical system works when the key switch is turned on. So, I'm guessing the key switch is still good.
So, I have a bunch of questions:
1. First, I want to get a clear answer to a question I have about information I see flying around a lot. QUESTON: If any of the safety switches is bad, my understanding is that the starter motor will not even crank, is that correct?
2. QUESTION: My starter motor always cranks, so does that mean that the safety switches have nothing to do with the function of the stop solenoid and I should not bother testing the safety switches?
3. QUESTION: Is there or is there not a relay that is connected to the stop solenoid? There is no mention of one in the service manual and I am too much of an idiot to tell if the schematic is showing a relay connected to the stop solenoid or not.
4. All the fuses are good and I have cleaned all the blades on the fuses with a brass brush. However, I unscrewed the fuse block and looked at the back, and there is some corrosion where one of the heavier gauge wires is attached to the back of the fuse block. I don't have a place indoors to store the machine, but I keep the cockpit and dashboard covered when I'm not using it. It would be good if I could replace the fuse block. QUESTION: Is there any way to clean the fuse block? Could I use baking soda like you can use on a battery terminal? QUESTION: How do you replace the fuse block? I can't figure out how you remove the wires from the back of the block. Are they soldered in place? QUESTION: Or, is the fuse block attached to the wiring harness, and you have to replace the whole harness?
5. On other forums, it's been suggested that it is a grounding problem. QUESTION: The rest of the electrical system works fine, and the starter motor cranks great, so I'm presuming it is not a battery grounding problem, is that correct? QUESTION: Exactly what would I be looking for if it is a ground problem? The solenoid itself is bolted to the engine, so that can't be it. Where would there be another ground that would be affecting the solenoid?
Any help would be greatly appreciated!
Now, my L48 is starting only occasionally. The problem has become worse over the last month, and now it almost never starts. I can clearly hear the stop solenoid click when it is working, and the motor starts right up. In the past, the motor would sometimes not start.....and there was no solenoid click.....and I'd let it sit 5 minutes and it would start and run all day. Now, if it starts, it may run for a couple of hours or it may die right in the middle of going up the driveway. And then, it will not start no matter how long I let it sit. A few days ago, I bought a new stop solenoid and installed it. I turned the key, heard the click, and it started right up. I turned it off 15 minutes later, and tried to restart it and there was no click and no start. 5 minutes later it clicked and started and ran the rest of the day, so I thought maybe I just had not turned the key all the way or something. Then the next day, it started right up, and I drove it 200 feet up my driveway and it died in the middle of the driveway. I had no way to move it and we could not go around it. I took the old solenoid, and sawed off the fuel stop rod, and took the new solenoid out and reinstalled the old one, and the motor started right up, so I know for certain that the solenoid is not actuating the stop rod. I now was able to move the machine. I was picking up debris along my driveway, so I kept the machine on the driveway and kept it running for several hours. I killed it by removing the air filters and blocking off the air intake with some folded up heavy-duty trash bags.
That's where I am now. I'm a rookie mechanic and electrical problems give me fits. I have the workshop manual, but I can't decipher everything in the schematic. In the manual, it says if the motor cranks but doesn't start, that the problem is the solenoid. Oh, and I also have a 1-year old key switch and I removed that and it looks brand new. Plus, all the electrical system works when the key switch is turned on. So, I'm guessing the key switch is still good.
So, I have a bunch of questions:
1. First, I want to get a clear answer to a question I have about information I see flying around a lot. QUESTON: If any of the safety switches is bad, my understanding is that the starter motor will not even crank, is that correct?
2. QUESTION: My starter motor always cranks, so does that mean that the safety switches have nothing to do with the function of the stop solenoid and I should not bother testing the safety switches?
3. QUESTION: Is there or is there not a relay that is connected to the stop solenoid? There is no mention of one in the service manual and I am too much of an idiot to tell if the schematic is showing a relay connected to the stop solenoid or not.
4. All the fuses are good and I have cleaned all the blades on the fuses with a brass brush. However, I unscrewed the fuse block and looked at the back, and there is some corrosion where one of the heavier gauge wires is attached to the back of the fuse block. I don't have a place indoors to store the machine, but I keep the cockpit and dashboard covered when I'm not using it. It would be good if I could replace the fuse block. QUESTION: Is there any way to clean the fuse block? Could I use baking soda like you can use on a battery terminal? QUESTION: How do you replace the fuse block? I can't figure out how you remove the wires from the back of the block. Are they soldered in place? QUESTION: Or, is the fuse block attached to the wiring harness, and you have to replace the whole harness?
5. On other forums, it's been suggested that it is a grounding problem. QUESTION: The rest of the electrical system works fine, and the starter motor cranks great, so I'm presuming it is not a battery grounding problem, is that correct? QUESTION: Exactly what would I be looking for if it is a ground problem? The solenoid itself is bolted to the engine, so that can't be it. Where would there be another ground that would be affecting the solenoid?
Any help would be greatly appreciated!
