L4060HSTC Running Issue- Help!

[Speedwell]

Hi folks,
I am new to the forum but I am looking forward to learning as much as I can about Kabota tractors.
I have a 4060HSTC. I backed it out of the shed, set the engine to idle, engaged the PTO to bush hog, raised the engine speed to 2000RPM and started mowing as usual. After just a minute or two the tractor decided to drop engine RPM down to idle speed all by itself, then after about 5 seconds increased back to 2000.
-I was in very short grass but raised the bush hog up just in case but it repeated the problem again.
-I turned off the PTO switch, which disengaged the bush hog but the problem persisted.
-I pulled the tractor back into the shed and turned it off so I could have a look.
-I rechecked all fluid levels, drive belt, etc. Also looked at the air filter (great condition, very clean).
-Tried to re-start the tractor and it turns over great but will not start.
-I checked all the fuses, removed the output line from the fuel pump and turned on the ignition, fuel flowed great.
-Checked the water separator and all is good there.
-The tank is full of fuel.
-Tractor has about 450 hrs on it.
Has anyone ever experienced this before or is the time to call the dealer and have them come get it?
Any suggestions would be most welcome, thanks!

 

[Roadworthy]

You may have a fuel flow issue. Remove the bowl from the fuel filter, replacing it with a bucket underneath. Watch to see if you get a good steady flow. If it slows after a bit or stops you've found your problem. If it continues to flow you know the problem is after that point.

 

[Speedwell]

Thanks for your reply. I am interpreting the term “bowl” as fuel separator as there isn’t a traditional bowl in this system. I checked fuel flow at the separator and it flows great. It also pumps fuel very well at the pump outlet, which is past the “bowl”.
When the fuel line leaves the pump, it goes to a rectangular unit on the side of the engine before it goes to the filter. I did just change the fuel filter and found that though fuel leaves the pump very well, it doesn’t come out of the bleeder on the fuel filter head.
I am thinking the fuel is being stopped at the “rectangular unit”, which appears to be vacuum operated.
I have ordered a shop manual in order to better understand how the fuel system works.
I am wondering if the ECU is stopping/restricting fuel flow through the “rectangular unit”, but there are no codes showing in the instrument panel.

 

[sheepfarmer]

This might help. There are some diagrams in this thread that should apply to your model. A shop manual is indispensable. I recommend you take it to the dealer before you mess with stuff further down the line before the high pressure pump and injectors.

https://www.orangetractortalks.com/...-systems-in-new-common-rail-l-tractors.34418/

 

[Speedwell]

I just had a closer look and realized that when fuel leaves the rectangular box it goes two places, the injection pump (I am guessing) and a fuel cooler. I guess I will just wait for the manual to arrive. My local dealers booked a month out.

This might help. There are some diagrams in this thread that should apply to your model. A shop manual is indispensable. I recommend you take it to the dealer before you mess with stuff further down the line before the high pressure pump and injectors.

https://www.orangetractortalks.com/...-systems-in-new-common-rail-l-tractors.34418/

Thanks Sheep Farmer! That link is super helpful. I’ll try cycling it with the key as I have tried everything else.
I still have no idea what caused this problem in the first place because the problem was present prior to changing the filter.

 

[Speedwell]

I just had a closer look and realized that when fuel leaves the rectangular box it goes two places, the injection pump (I am guessing) and a fuel cooler. I guess I will just wait for the manual to arrive. My local dealers booked a month out.

Thanks Sheep Farmer! That link is super helpful. I’ll try cycling it with the key as I have tried everything else.
I still have no idea what caused this problem in the first place because the problem was present prior to changing the filter.

This might help. There are some diagrams in this thread that should apply to your model. A shop manual is indispensable. I recommend you take it to the dealer before you mess with stuff further down the line before the high pressure pump and injectors.

https://www.orangetractortalks.com/...-systems-in-new-common-rail-l-tractors.34418/

Ok, it’s fixed! I turned the engine over for about 5 seconds, waited 30 seconds, then turned it over for 5 seconds……….etc. It started on the 6th cycle and is running perfectly. I’m still not sure what the original problem is but it seems to have gone away. It have simply been water in fuel, then wouldn’t prime after I broke the system open.
All is well now though.
Thanks Sheep Farmer!!!!

 

[Jchonline]

Ok, it’s fixed! I turned the engine over for about 5 seconds, waited 30 seconds, then turned it over for 5 seconds……….etc. It started on the 6th cycle and is running perfectly. I’m still not sure what the original problem is but it seems to have gone away. It have simply been water in fuel, then wouldn’t prime after I broke the system open.
All is well now though.
Thanks Sheep Farmer!!!!

Seat safety switch also catches people off guard in some cases. If you don't have weight properly distributed in the seat, the safety will engage and kill engine rpm. Not saying this is what happened to you but something to be aware of with sudden rpm drops.

 

[Speedwell]

Seat safety switch also catches people off guard in some cases. If you don't have weight properly distributed in the seat, the safety will engage and kill engine rpm. Not saying this is what happened to you but something to be aware of with sudden rpm drops.

Excellent advice, thank you!

 

[whitetiger]

Excellent advice, thank you!

The seat switch has nothing to do with the cranking, starting, or running of the tractor when it is in neutral.


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