Question about diesel fuel color/clarity in tank LX 3310HSDC

[Jeffcall720]

Sorry in advance if this is a dumb/easy question, but I appreciate any insight. I have an LX3310 HSDC that is around 75 hours right now of light use, mostly mowing. 20+/- hours a year. I had my full 50 hour service performed at my Kubota Dealer. I am having a problem now where it runs fine until 20 minutes into mowing, then like a switch it starts to bog down and has trouble keeping speed in turns, going uphill, and maintaining the PTO RPM, and sounds about like it could stall if I didn't let up on the treadle - but yet it can idle fine. No exhaust smoke at all when this happens. It can also mow fine on the flat and downhill straight when this is happening. It's just under load when the problem happens. My air/fuel separator looks good and drains fuel, I have verified all of my air filters and radiators are clear, and it is not overheating based on the gauges. I am going to change my fuel filter, but I looked into the tank to see if I saw any foreign objects, material, etc - and this is the color of the fuel in there. I always use highway-taxed diesel from a major fuel station near me. I have never had stale fuel issues or seen diesel get contaminated or go bad - but honestly I don't use this tractor sometimes for months at a time. Is this an abnormal appearance for diesel in the tank? I'm probably going to drain it and flush out the whole system with new diesel and put a stabilizer in it and see how it goes, and I'll looks for diesel crud in the bottom of the tank/filters/etc. I was just surprised about how cloudy and fluorescent blue the diesel looks. No additives have been used in this tractor so far, by the way. I'm in Maryland, FWIW, and it doesn't get really cold here. Sorry if this is a dumb question!

 

[Edke6bnl]

Try for fun to remove fuel cap, could have a plugged vent cap

 

[Jeffcall720]

Try for fun to remove fuel cap, could have a plugged vent cap

Thanks, I tried that, it did not change what was happening. And I did not hear any negative pressure when I cracked the cap open after it was happening while running.

 

[Mitjam]

Thanks, I tried that, it did not change what was happening. And I did not hear any negative pressure when I cracked the cap open after it was happening while running.

Definitely sounds like a fuel issue. If you’re not sure I would siphon out the old diesel, fill with new fresh and change fuel filter and check your fuel seperator canister. These motors with ECU will derate if the motor is running hot or not getting the proper charged air from the turbo. Just check your radiator and air filter also too. The little rad infront is for your fuel cooler. Check the all the clamps for correct tension coming from turbo to intake manifold also. Good luck

 

[Russell King]

I suspect that the fuel color being bluish is fro the LED light that is shining in through the tank fill port or the camera reaction to the light reflecting off the fuel.

But you can either siphon or drain some into a glass jar and look at it under normal light.

But it shouldn’t be blue, red maybe for off road but I would say it should be clear amber color.

 

[Jeffcall720]

I suspect that the fuel color being bluish is fro the LED light that is shining in through the tank fill port or the camera reaction to the light reflecting off the fuel.

But you can either siphon or drain some into a glass jar and look at it under normal light.

But it shouldn’t be blue, red maybe for off road but I would say it should be clear amber color.

Good thought, thanks. I will siphon some out and see what it looks like outside the tank. I just wasn't sure what bad, sludgy, fouled diesel looked like.

 

[Jeffcall720]

Definitely sounds like a fuel issue. If you’re not sure I would siphon out the old diesel, fill with new fresh and change fuel filter and check your fuel seperator canister. These motors with ECU will derate if the motor is running hot or not getting the proper charged air from the turbo. Just check your radiator and air filter also too. The little rad infront is for your fuel cooler. Check the all the clamps for correct tension coming from turbo to intake manifold also. Good luck

Thanks for the ideas, I did not know these would derate themselves like that, but it makes sense. That's what is feels like. Radiators are all blown out both directions as well as the screens and filter canister are cleaned out. Operating temp seems good, at least from the light bars on the dash, for what those are worth. I'll do the fuel system clean out and check around for loose clamps like you said.

 

[Mitjam]

Thanks for the ideas, I did not know these would derate themselves like that, but it makes sense. That's what is feels like. Radiators are all blown out both directions as well as the screens and filter canister are cleaned out. Operating temp seems good, at least from the light bars on the dash, for what those are worth. I'll do the fuel system clean out and check around for loose clamps like you said.

It’s a long shot but might save a yourself a trip to dealer.

 

[Runs With Scissors]

What rpm's are you maintaining when it happens?

Could you possibly be "lugging" the motor, or not keeping the rpm's in the "sweet spot"?

 

[Jeffcall720]

What rpm's are you maintaining when it happens?

Could you possibly be "lugging" the motor, or not keeping the rpm's in the "sweet spot"?

When I start, I crank the engine speed up to where the mower is 520+/- RPM, and it does fine as it always has, through thick stuff, tight turns, and uphill - no lugging whatsoever. But then right around 20-25 minutes in, all of the sudden it flips like a switch and changes it's mind - and I first notice when I turn at the end of a row, I hear the engine slow down, and then nearly every load it experiences causes it to slow more, unless I stop asking it to do stuff, and then the speed comes back up. PTO RPM speed will down into the low 400's, or lower if I didn't lift off the pedal. It just suddenly decides to be really weak, like it has lost half it's power.

 

[D2Cat]

I'd double check the fuel filter (even though you indicated full service) making sure nothing is blocking flow. If you had a growth of algae in the fuel tank you'd have the appearance of gummy snot in the tank and in fuel lines.

 

[Jeffcall720]

I'd double check the fuel filter (even though you indicated full service) making sure nothing is blocking flow. If you had a growth of algae in the fuel tank you'd have the appearance of gummy snot in the tank and in fuel lines.

Absolutely, hopefully it will fix it!

 

[S-G-R]

Any updates?

 

[Jeffcall720]

Any updates?

Just picked up the filters yesterday actually, so I'll be changing them later this week and I'll update here.

 

[fried1765]

Just picked up the filters yesterday actually, so I'll be changing them later this week and I'll update here.

I find these "old diesel fuel" posts to be rather perplexing.
I do understand the need for "fresh" filters.
But,.......diesel is stored for years at a time, in other areas of the world, and it is still usable.
Are the new "common rail" systems so finnicky that the fuel must absolutely be "fresh".
Wonder what Rudolph Diesel would think/say!

 

[Old Machinist]

Are you sure it's not trying to go into regen? Any lights illuminating on the dash? You might just need to do a parked regen. I have the same tractor and bought it with 200 hours on it. I didn't run it an hour before it did a regen then it pulled another at 220 hours. I'm at 254 hours now and it hasn't tried again.

PTO speed on mine is at wide open throttle or 2500 RPMs on the tach.

Seems I have seen pump fuel take on that look in a tank. If it's clear as it looks I wouldn't suspect it to be the issue. I use off road so it's red. I have fuel delivered and always treat the stored fuel with biocide and lubricity additive. Letting untreated fuel sit is a recipe for algae disaster. If you find black sludge in the filter you will need to drain and clean the tank. I had to do that on my JD after I bought it and used a shop vac to get it all out.

This model tractor has several "Fix as Fails" bulletins on them. They are covered for 5 years after the in service date for free repair at the dealer.
1 - Does it have a strong exhaust smell when it does it? There is a bulletin on that.
2 - The injectors may become defective due to manufacturing variations and operating environment, causing engine power drop only when coolant temperatures are above 60 degrees Celsius (140 degrees Fahrenheit). There is a bulletin for that. Serial numbers effected on this one is tricky so contact the dealer with your serial number and see if it applies. This one MAY be your issue.

There are 3 others but not related to running or performance.

 

[Jeffcall720]

Are you sure it's not trying to go into regen? Any lights illuminating on the dash? You might just need to do a parked regen. I have the same tractor and bought it with 200 hours on it. I didn't run it an hour before it did a regen then it pulled another at 220 hours. I'm at 254 hours now and it hasn't tried again.

PTO speed on mine is at wide open throttle or 2500 RPMs on the tach.

Seems I have seen pump fuel take on that look in a tank. If it's clear as it looks I wouldn't suspect it to be the issue. I use off road so it's red. I have fuel delivered and always treat the stored fuel with biocide and lubricity additive. Letting untreated fuel sit is a recipe for algae disaster. If you find black sludge in the filter you will need to drain and clean the tank. I had to do that on my JD after I bought it and used a shop vac to get it all out.

This model tractor has several "Fix as Fails" bulletins on them. They are covered for 5 years after the in service date for free repair at the dealer.
1 - Does it have a strong exhaust smell when it does it? There is a bulletin on that.
2 - The injectors may become defective due to manufacturing variations and operating environment, causing engine power drop only when coolant temperatures are above 60 degrees Celsius (140 degrees Fahrenheit). There is a bulletin for that. Serial numbers effected on this one is tricky so contact the dealer with your serial number and see if it applies. This one MAY be your issue.

There are 3 others but not related to running or performance.

Contacted the dealer today. Of course, they had the same thoughts as everyone - stuff in tank, old fuel filter, etc etc, but they agreed I had taken care of pretty much every item so far, and the problem is just too repeatable and specific time-wise when it occurs. They asked me to send them a video of the tractor having the issue, and I also asked them to look into that TSB. I'm currently 2.75 years out from my in-service date, and this is my selling dealer - so fingers crossed they work hard on the issue for me.