Preventing water intrusion into fuel?

RalphVa

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Jan 19, 2020
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Charlottesville
When fueling up about 3 weeks ago at the corner station, a clump of snow fell into my fuel tank! The clump must've been somewhere above the nozzle, and I didn't see it until it fell. It sat before my amazed eyes for an instant between the nozzle and the rim of the tank opening. The clump was about 2/3 the size of a fifty cent piece, I'd say.

How big a problem do I have!?

I was and am using Hot Shot's winter anti-gell, which I think has water dispersers too. I have filled up twice since then. No problems with running. I use highway diesel because they sell a lot of that at this station but seem to move comparatively little off-road diesel.

My tractor has about 85 hours and I have not changed the fuel filter yet. Filter looks good, per a Kubota technician who was here helping fix a loader issue.
Wow! Glad it has not caused a problem.

I went 400 hours before I changed the fuel filter on the JD 2025R (only one is in the water bowl on gen. 1).

Present Isuzu filter is at 230 hours, and a spin-one after the small fuel pump. Plan to replace this year at the 10 year mark.
 
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SRRGC1

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From what I have read, ULS diesel fuel, either on road or off road, is required to be of the ULS which I believe is <15 PPM. This is what my Kubota's currently recommends. I would be careful using too much #1 diesel due to lubrication issues as mentioned in other posts. Not sure what the newer "regen or DEF" engines require. I always use "HOWES" diesel treat year around and keep fuel tank full.
 

PoTreeBoy

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Here's a good article on water in diesel fuel. The jist is a very small amount of water can dissolve in diesel fuel. It's not absolutely dry even when it leaves the refinery. Since it's dissolved, no filter will remove it. But as long as it's dissolved it doesn't cause any problem.

The problem is that the solubility changes with temperature - warm fuel can dissolve more water than cold (similar to air and water). So water that was harmlessly dissolved in 70° fuel can form minute droplets as the fuel is cooled. This can be separated out. But these droplets can freeze before they get to the filter, or in the filter, causing blockage, unless a fuel antifreeze is used, either by the distributor or the user.

Jet engines, which commonly operate in cold conditions, often have fuel heaters to melt the ice crystals to keep them from plugging the fuel filters. But sometimes the crystals would plug the heaters. So fuel antifreeze called Prist is commonly added to the fuel to prevent ice crystals from forming.

 
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Mossy dell

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B2601 (2021) JD970 (1998) B2100 (1991) B6100E (1988)
Jul 20, 2020
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Excellent article! Thanks, PoTreeBoy. So far, no problems. But I haven't used the tractor in a couple of weeks, no snow to plow, and plan to empty the bowl in the next day or two. I have a filter too but didn't realize the rubber o-rings do not come with filters. So it's a minor risk of tearing one during replacement till I have spares.
 

RalphVa

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Jan 19, 2020
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Charlottesville
Excellent article! Thanks, PoTreeBoy. So far, no problems. But I haven't used the tractor in a couple of weeks, no snow to plow, and plan to empty the bowl in the next day or two. I have a filter too but didn't realize the rubber o-rings do not come with filters. So it's a minor risk of tearing one during replacement till I have spares.
I see no reason for just emptying the fuel bowl. Like I said above, my 2025R went 400 hours on its bowl filter, and the Isuzu is at 230 hours and over 9 years. Unless you see a layer of water in the bottom of the bowl, there's no reason to empty it.
 

RalphVa

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Jan 19, 2020
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Charlottesville
If I had a snow blower, I think I'd use a small towel and stuff it above and around the fuel filler cap and then put some plastic on top the towel and stuff it around the sides. It can still get air through the towel, which will be kept mostly dry via the plastic on top. Think there are air inlets around the bottom side of the fuel cap.
 

Mossy dell

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B2601 (2021) JD970 (1998) B2100 (1991) B6100E (1988)
Jul 20, 2020
274
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sw VA
I see no reason for just emptying the fuel bowl. Like I said above, my 2025R went 400 hours on its bowl filter, and the Isuzu is at 230 hours and over 9 years. Unless you see a layer of water in the bottom of the bowl, there's no reason to empty it.
I don't see a line in the bowl. But my manual says if dirt or water has entered the fuel system, to clean the bowl and filter periodically. Also to do so at 100 hours, which I am coming up on. For the price of a filter I'll probably just replace it—don't have much confidence in my ability to clean it.
 

Mossy dell

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B2601 (2021) JD970 (1998) B2100 (1991) B6100E (1988)
Jul 20, 2020
274
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sw VA
I dumped my bowl but saw no clear separation in it indicating water. JD has a red ring in the bottom of its fuel bowl in the 1025R that floats when there's water. Has anyone tried using one in a Kubota? It would be handy, easy to spot when it floats up from the bottom.

Could not get out the o-rings in the fuel filter so ordered them and probably will change the filter soon. But it doesn't look very dirty, and there was no dirt or sediment in the bowl so a change probably isn't needed.

I have seen no evidence or effect from the small clump of fluffy snow that fell in my tank a month ago! Hope the water didn't blow through the injectors. I hope the filter system worked even if I could not discern any water in the bowl.
 

NCL4701

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I dumped my bowl but saw no clear separation in it indicating water. JD has a red ring in the bottom of its fuel bowl in the 1025R that floats when there's water. Has anyone tried using one in a Kubota? It would be handy, easy to spot when it floats up from the bottom.

Could not get out the o-rings in the fuel filter so ordered them and probably will change the filter soon. But it doesn't look very dirty, and there was no dirt or sediment in the bowl so a change probably isn't needed.

I have seen no evidence or effect from the small clump of fluffy snow that fell in my tank a month ago! Hope the water didn't blow through the injectors. I hope the filter system worked even if I could not discern any water in the bowl.
Mine came with a red float ring. Kind of surprised they aren’t all that way.
 
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