2016 L6060 cab fuel issues

DSGrouse

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Equipment
2016 Kubota L6060
Aug 31, 2023
4
0
1
Central Va
I've been dealing with this for a while, and have done some lurking and reading. I've found a thread with a similar issue with a cab l6060, but I haven't quite been able to figure out a solution.

I checked my screen in the water separator, as always, it's nearly perfectly clean with 0 water. Last fall, (I had the same issue) I replaced the fuel filter, fuel pump rd411-51353 from Messicks, bled the air, and bled the air out of the injectors and it ran, but not well. Due to time constraints, I put it up for the winter. I used it off and on for short tasks. A few weeks ago, I started grading our long dirt road and it was back to starving within a half hour.

When going up or down even the slightest hill, the tractor would starve out. Check the temperature on the new kubota RD411-51353 fuel pump; it would be crazy hot.

I thought that was the same issue as in the post I linked above so I set about transferring the fuel out of the fill side; 5 min in, the fuel side was empty, and there wasn't any fuel from the draw side making it back over. So, I don't think it is the check valve. There was almost 0 debris/sediment in the fill side tank. I suppose the check valve could be stuck closed, creating a hard vacuum for the small RD411-51353 pump.


I emptied the water separator with negligible sediment and reinstalled it. It filled quickly, but when bleeding the air out of the filter, the small pump only seemed to deliver fuel when turning the key. The tractor started and died within a few seconds of running. Bled the air out of the filter again, but no fuel moved until I cranked it over.

Maybe I got a bad fuel pump?
Maybe the check valve is stuck?

I get fuel into the water separator without issue; when the tractor starves and dies, the water separator is full of fuel. If there was a sediment problem in the tank or a stuck check valve, wouldn't the separator empty of fuel as the tractor ran out?

So, I put it all to you, WTFBBQ. I am at my wit's end diagnosing this.

Is there a way to check the check valve without having to drop both tanks?

Can I take the steel guard off the 030 Crossover tube and use the cross-over tube to drain the pickup side tank?
 

North Idaho Wolfman

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You need to find out if your getting fuel flow out of the tanks.
Then worry about if the fuel is transferring tanks or not.
Would not be the first time a check valve flap has ended up blocking output.
 
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Workerbee

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Zd21
Mar 1, 2020
157
45
28
MN
Ive seen the insides of rubber fuel lines collapse on outboards. Id see that all the fuel paths are unobstructed.
 
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DSGrouse

New member

Equipment
2016 Kubota L6060
Aug 31, 2023
4
0
1
Central Va
You need to find out if your getting fuel flow out of the tanks.
Then worry about if the fuel is transferring tanks or not.
Would not be the first time a check valve flap has ended up blocking output.
I thought I put this above, but if i didn't I apologize. So the water separator fills quickly and never runs out of fuel when the tractor bogs down and shuts off. When I pull the separator glass off and turn the key fuel comes out.

Ive seen the insides of rubber fuel lines collapse on outboards. Id see that all the fuel paths are unobstructed.
I've been reading a bunch of posts like mine and I admit that I've not checked the fuel lines to see if they are collapsing. I need to check and see if the FP holds a vacuum when turning the tractor over.
 

kubotafreak

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GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Sep 20, 2018
1,022
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83
Arkansas, US
Ill give my two cents. That flap between the tanks is to prevent flow back to the non feeding tank on hills. The easiest way to damage the flap is by blowing compressed air back to the tank. This is a poor technique since it is meant to break up a clog. Well the clog will just reconstitute again, so not a real solution. As far as sediment, it is a plastic tank so other than your dust/bugs/grass from opening the cap, it wont have rust. Most likely clog is in the feed side of the sediment bowl. You need to remove it and use a pick to scrape the black collected gunk out of it. There is also a vent in the return reserve tank on the shutter plate. It is between the cab and engine. Perhaps a dirt dauber clogged it up. Another likely culprit is the radiator being clogged up. You need an air wand to clean it properly. I dont advise water until the dry debris is removed. The water first technique will cause mud to form, which is much harder to remove. These machines over heat easily, the gauge is not always going to indicate elevated temps, before the ecu rolls back fuel.
 
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DSGrouse

New member

Equipment
2016 Kubota L6060
Aug 31, 2023
4
0
1
Central Va
Ill give my two cents. That flap between the tanks is to prevent flow back to the non feeding tank on hills. The easiest way to damage the flap is by blowing compressed air back to the tank. This is a poor technique since it is meant to break up a clog. Well the clog will just reconstitute again, so not a real solution.
Yeah, I've not blown air in. When i started having this problem, i asked around and was warned against doing that."

[QUOTE}As far as sediment, it is a plastic tank so other than your dust/bugs/grass from opening the cap, it wont have rust. Most likely clog is in the feed side of the sediment bowl. You need to remove it and use a pick to scrape the black collected gunk out of it. [/QUOTE]

My sediment bowl has always been fairly clean. Could you show me on the diagram where you are talking about?


Capture.JPG


There is also a vent in the return reserve tank on the shutter plate. It is between the cab and engine. Perhaps a dirt dauber clogged it up.
Same question could you point it out on the diagram?
1670789478960.png


Another likely culprit is the radiator being clogged up. You need an air wand to clean it properly. I dont advise water until the dry debris is removed. The water first technique will cause mud to form, which is much harder to remove. These machines over heat easily, the gauge is not always going to indicate elevated temps, before the ecu rolls back fuel.
I am pretty diligent about blowing my radiators out. I took a look tonight and there is minimal debris and no caked anything. That being said, I'll blow them out tomorrow and see if that will help.

Right now, it will start but not run for very long, It makes me think there is gunk in the lines or on the feed side of the sediment bowl of the water seperator. It fills up without issue. If we turn the key to start, the fuel filter fills, and i can purge any air. but the tractor only runs for a few moments.
 

kubotafreak

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Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Sep 20, 2018
1,022
374
83
Arkansas, US
The arrow (10) points at one of the elbows. Some take the shut off valve apart as well.
As far as the vent its item (130)
 
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xsf18cdf

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L6060 HSTC
Nov 15, 2023
9
3
3
Texas
Thanks for the quick replay and confirmation.

Debris in tank that settles when there is no demand and obstructs when flow begins. That's why it will start, run for awhile then stop. Plastic tanks have debris from the factory and can take awhile to obstruct.
Just my $00.02.

X
 

fruitcakesa

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Equipment
M 6040
Oct 26, 2010
852
265
63
Cavendish Vermont
A while ago my m6040 was having fuel issues where it wouldn’t fire although it had cranked over fine. After going through all the testing similar to you, I decided that the hose coming off elbow # 10 was somehow not sealing well.So a replacement hose was added and that took care of the problem. My tractor was maybe 8 years old then. I also noticed that elbow 10 was loose in its fitting so I just twisted it to get a better seat
 
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