Normally my little workhorse is totally reliable but yesterday it refused to restart. I had been using it to move a small goods trailer around the yard so it wasn't a cold start problem. It would fire and start but as soon as I released the key it would die. It seemed like if I would hold the key in the "Start" position it was happy to stay running. Good fuel, recent new filter and the battery is in good state of charge, although it took a hammering trying to start so I ended up jump starting it from my Ford van. I'm really at a loss to know why it was doing it. Anyone got any ideas? I didn't shut it off until I put it back in the shed just in case it refused again.
B5100 starting problem
- Thread starter Aardvark
- Start date
Yes, I tried the engine stop thing several times but no change. I was wondering if there was something inside the pump that had stuck. Just guessing really. Half a tank of fuel, filter was changed about 2 hours (running time) ago, and I loosened the two bolts at the top of the filter to check there was no air there. I will get out there today and see if it starts as normal. Fingers crossed.
No luck starting it. Pretty well stuck now because I can't get another vehicle near it to tow it away from the other stuff behind it. 
Sounds like the engine is fine. The switch is activating the starter. Does the engine only run when the starter is turning it over? Have you tried jumping across the starter and bypass the switch?
I think the only thing to shut off the engine is lack of fuel in that model. Have you checked to be sure the decompression lever is actually moving when you push/pull the knob? (Check at front of valve cover)
I think the only thing to shut off the engine is lack of fuel in that model. Have you checked to be sure the decompression lever is actually moving when you push/pull the knob? (Check at front of valve cover)
"The switch is activating the starter. Does the engine only run when the starter is turning it over?"
Yes, that pretty much describes it.
"Have you tried jumping across the starter and bypass the switch?"
No, but I will try it and see what happens.
" Have you checked to be sure the decompression lever is actually moving when you push/pull the knob? (Check at front of valve cover) "
Thanks for the suggestion. I'll check that out while I'm at it.
Yes, that pretty much describes it.
"Have you tried jumping across the starter and bypass the switch?"
No, but I will try it and see what happens.
" Have you checked to be sure the decompression lever is actually moving when you push/pull the knob? (Check at front of valve cover) "
Thanks for the suggestion. I'll check that out while I'm at it.
North Idaho Wolfman
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Make sure the bleeder valve on the side of the injection pump is closed (turn to the right till it stops).
If you manually jump the starter you should also jump the glow plugs.
When you got it started the last time, how did it run?
Did it have plenty of power? Any smoke?
If you manually jump the starter you should also jump the glow plugs.
When you got it started the last time, how did it run?
Did it have plenty of power? Any smoke?
Last edited:
"When you got it started the last time, how did it run?
Did it have plenty of power? Any smoke?"
Was running normally. A bit of black smoke on startup and then nothing after that while running.
UPDATE
I just got it running. While checking things out ready to bypass the starter I had a high intensity LED light pointing at the back of the ignition switch. I discovered two plastic inline fuse holders tucked up in the corner. I managed to get them apart to check the fuses and found a 15A fuse had blown. New fuse in place it started instantly! Happy Day.
I have no idea what that fuse does with respect to a diesel engine but it seems to have solved the issue. If I can get my hands on a workshop manual I will check out the wiring schematic for more info.
Many thanks to everyone who took the time to respond to my posting. Much appreciated.
Did it have plenty of power? Any smoke?"
Was running normally. A bit of black smoke on startup and then nothing after that while running.
UPDATE
I just got it running. While checking things out ready to bypass the starter I had a high intensity LED light pointing at the back of the ignition switch. I discovered two plastic inline fuse holders tucked up in the corner. I managed to get them apart to check the fuses and found a 15A fuse had blown. New fuse in place it started instantly! Happy Day.
I have no idea what that fuse does with respect to a diesel engine but it seems to have solved the issue. If I can get my hands on a workshop manual I will check out the wiring schematic for more info.
Many thanks to everyone who took the time to respond to my posting. Much appreciated.
Here we are, three months later and it is doing it again. Symptoms exactly the same as before. Won't start and stay running. It runs as long as I keep the key turned to the "start" position but dies as soon as I let go. I went straight for the fuse behind the dash that was blown before but this time it doesn't work. In fact it keeps blowing the fuse (15A). I have looked through all the documentation I can find and in the owner's manual it mentions two fuse holders that take 5A and 3A fuses supposedly to protect the electrical system. What I can't get my head around is how either of these can stop the thing from running. If they controlled a fuel stop solenoid in the injection pump then I could understand it, but I don't think there is one. My love affair with Kubota is going off the boil.
Anyone have any suggestions? Once again, it is stopped somewhere I can't get another vehicle in to tow it to a safe place.
Anyone have any suggestions? Once again, it is stopped somewhere I can't get another vehicle in to tow it to a safe place.
kubotasam
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I suspect that your glow plugs are not getting the power when the switch is in the preheat position. I am assuming that a B5100 is similar to a B7100. When the switch is in the preheat position power comes from the switch into the glow plug indicator coil (little round hole in the dash) then to the glow plugs. The indicator coil (resistor) drops the battery voltage down to around 9 volts. After the switch is moved from preheat to the start position the glow indicator is bypassed and the glow plugs receive full battery voltage (which is dropped down because of the load of the starter). If you have a meter or test lamp check to see if the glow plugs are getting power when the switch is turned to the preheat position.
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Can you post a picture of the Injection pump and any thing around it?
Looking for a stop solenoid, that would be the only thing that explains your issue.
Looking for a stop solenoid, that would be the only thing that explains your issue.
The glow plugs are getting power and working normally. Thanks for the suggestion.
That was my line of reasoning. Sorry no photo but if there was a solenoid there would be a wire leading to it, and there are no wires or connectors in the area.Can you post a picture of the Injection pump and any thing around it?
Looking for a stop solenoid, that would be the only thing that explains your issue.
I decided to try a full air bleed, starting with the two points on the fuel filter housing. No joy. Then did the one on the top of the injection pump and to my amazement, it started!
. Then to cap it off, I had a look at the fuse I have been replacing (8 times) and it has blown again. The tractor starts fine now. I am assuming it was an air in the system issue all along and for some reason the blown fuse behing the dash serves no purpose. All electrics & lights work with it blown. Back to work now. Thankyou all for your input.