Kubota B7800 Not Starting, fuel line issue?

[Bill Martin]

This tractor has been an MVP for 10 years. Ran just fine two nights ago with multiple startups. Yesterday it wouldn't start. Turns over, battery is powered, everything seems normal but it won't start up. Thinking it was a fuel problem, I opened up the fuel filter, drained it, bled the lines, and met the same problem. Filter hasn't been changed in awhile so I'm picking up another one tomorrow. We've had cold temperatures so maybe I've got a bit of water in the line that's geling? Tank is full. I think there might be another place to bleed up by the fuel injector so I will also check that tomorrow. What else am I missing? Fuel pump problem maybe?

 

[BigBlue1]

Is it abnormally cold there? Is it possible fuel in your area isn't winter blended and has gelled. #2 can gel at 10-15*F. You said you bled the lines, so that would imply fuel was liquid, but gelling was the thing that made the most sense.

 

[GrandpaSmurf825]

Generally even in a gelled situation they start and then die. Last time my work truck gelled I started it to warm up and got out and headed to the house. Made it about 10 steps and it died. It would restart and die. This sounds like it didn't even try. I would check fuel shutoff solenoid.

 

[jk96]

If its cold check the fuel water seperator. That filter is a very fine mesh. Gelled fuel will build up with wax around that filter screen. Mine gelled up 2 days ago. Was able to move it into the garage overnight with a temp in the 40s. In the morning I still had a lot of wax buildup around the screen. Had to tap it several times to get the wax particles to drop to the bottom and get it running with some now treated fuel.

 

[dodge man]

How is your battery? Load test it. It may turn it over but not fast enough. Are the glow plugs working?

 

[Bill Martin]

Thanks all. I'm inclined to believe that the diesel fuel has gelled around the filter. It is liquid but we have been in the single digits several nights in a row now. I still don't have it started because we haven't gone above freezing but have a new filter and plan to wait until we go above freezing in a couple of days. The battery is fine and the glow plug light is coming on. Again, everything was fine the day before we got a very hard freeze. Will check back in a few days and let you know. Again, thanks.

 

[GrandpaSmurf825]

I attached a photo of the fuel shut off. It should activate or pull in when you turn the switch on. If it doesn't then that's where you need to start looking. I see they also have a system they call OPC which in layman's terms means if you fall off the tractor dies. There is a whole logic chart to that. It's also possible the issue is there especially with the cold weather. There is a switch inside the seat and vinyl gets extremely stiff and might not be making the safety switch since you said it's really cold.

https://www.orangetractortalks.com/forums/attachments/b7800-hsd-supplement-engusa-9y011-13031-pdf.45475/

 

[sixdogs]

Do you have more than half a tank of fuel? My B7800 wouldn't start after a filter change unless I did. Also, when I changed the filter mine was often hard starting the first time and I just gradually kept at it until I saw the fuel bowl fill. After a couple hours I could get it started but not sure why all that happened.

Also, I once had an issue with one of the large super fuses--50 amp-and for some reason it had blown. Changed it and back to work.

I would stick with these easy things before digging too deep and possibly creating more problems.

 

[CalG]

My own B7200 is a hard starter when cold.
even 45 seconds of glow plug heating won't get it to go when it's 5 degrees F , as it has been for the past week or so.

I throw an old moving blanket over the engine hood, put a 1500 watt space heater under the crankcase, and go away for 1/2 hour. She starts right up with "normal winter" 30 second glow heat.
OH! I put the battery on the charger at the same time.

Last night it got down to about 10 below, Needing to move the tractor this morning, I gave a "less than a second" blast of starting ether into the air cleaner inlet bell. Then a 30 second glow heat, ...

She started right up and much smoother than expected.

I run anti-gel in the fuel all winter on all the Diesels.

 

[Bill Martin]

On the first day that the single digit nights and teens and 20s days ended, she cranked right up. I learned a lot about how cantankerous diesel can be in very cold temperatures. I’ve also learned about putting anti-gel in the diesel, something I didn’t know was a thing. But I got WAY behind on snow removal and am now playing catchup. Thanks all. I’m ready to move into early Spring. Thanks all.

 

[jonsstihl]

glad you got it working. If it cranks its not a safety switch. now you know you should treat the fuel. I use power service but everyone has their own miracle product. The only time I had any problems was one year at christmas time when I figured I hadn't burnt the whole tank of #2 before the weather turned cold so I start treating my fuel in september so I don't get caught again.