Kubota u-15 running rough/hot

[groundworker]

Hello all,

Can anyone point me in the right direction please

Having some running issues with Kubota u15. Sounds rough like it's not running on all cylinders. Starts off minor then gets worse, loses revs and will stall under load if not careful.

I took this to be a fuel issue but checked and it was getting diesel everywhere including to injection pump. Thought maybe it was a blocked injector. Drained tank and hoovered some crap out of bottom. Ran fuel system cleaner through too.

However it is still happening and the machine is getting very hot. Coolant isn't boiling over but whole engine bay is hot even sat in the seat. Obviously it's been very hot weather wise the last few days but even last week when it was milder I had the same issue.

Where's the best place to start looking into the cooling system? Coolant level is fine but no idea when last changed. Some crud in the radiator.

I want to flush the system through but getting access to rad bottom hose was a pig when I tried earlier. As is the water pump.

Any easier places to start? Any ideas why it would run rough just because it's getting hot?

Cheers

 

[Vinpetrol]

Does it have a fly screen to protect the radiator ? I’ve seen machines running very hot when that gets choked with dust and limits the air flow through the rad

 

[V8Druid]

fuel filters, including any inline/banjo union filters ... if blocking up it will run 'lean' and overheat quickly, 'specially when the ambient is like it has been the last few days .. plus as Vin says, rad also needs to be very clear to function in these temps.

 

[doobin]

If it gets worse as it gets hotter check fuel hoses for cracks, air leaks around unions or collapsing under vacuum.

If it's an older machine I'd just replace the lines as a matter of course.

Blow your rad out with an airline- you'll be amazed the amount of dust that will collect there in dry, dusty conditions like these.

 

[groundworker]

No fly screen on the rad but it doesn't look in great condition.

Washed it out but there wasn't much crud in there. Will blast with compressor at the weekend.

Can't see any cracks on fuel lines, they look ok for 15 year old machine.

Have changed the inline filter and so far so good today - have been working it hard with pecker on for a while. However I haven't put all the bodywork back on yet so maybe that's making the difference. It's certainly kicking out some heat on to my legs.


Thanks for the help guys.

 

[Steve]

Does it have the D782 engine? I think I read somewhere else that they had pump issues, seem to remember it was a common enough problem that you can get a pattern rebuild kit for sensible money.

 

[V8Druid]

No fly screen on the rad but it doesn't look in great condition.
Washed it out but there wasn't much crud in there. Will blast with compressor at the weekend.
Can't see any cracks on fuel lines, they look ok for 15 year old machine.
Have changed the inline filter and so far so good today - have been working it hard with pecker on for a while. However I haven't put all the bodywork back on yet so maybe that's making the difference. It's certainly kicking out some heat on to my legs.


Thanks for the help guys.

have you checked for gauzes in any banjo unions -- they're worse culprits than in line-ers for starving fuel

don't often see an internal gauze ... usually external like the above around the bolt, not inside it - but they do exist

as do these

 

[groundworker]

Had another look at this today (only been ten months)

Took much of the fuel system apart looking for these filters^^. Put it all back together and it is not running on all cylinders and very quickly dumps a LOT of engine oil out of the breather. Can’t work that out at all so take it apart again and find this at the injection pump - middle port is different to the outer two.

Looks like I have missed a part or put it together back to front?

Find this pic on google, looks like rod/plunger has dropped down too far. Could this be causing diesel to be pumped into the crankcase?

 

[groundworker]

Does it have the D782 engine? I think I read somewhere else that they had pump issues, seem to remember it was a common enough problem that you can get a pattern rebuild kit for sensible money.

Yes that's the one.

Just found this parts diagram from the injection pump.

---

I'm looking at that now thinking part 030 is missing and fuel is passing straight through, I don't know if that goes to the crankcase.

Definitely need to find that part, must have dropped down below the engine

 

[groundworker]

Actually managed to find it amongst the crud.

Fitted it and put everything back together expecting to run ok after bleeding but not getting any fuel last the injection pump.

Getting to the inlet but nothing out at all, any ideas??

 

[heritage machining]

I have had engines that need to be pumped on the inlet to the diesel filter whilst cranking to bleed up just fit a inline primer bulb in the feed line