L3902 fuel problems

[DSGarcia]

My L3902 is only one year old. Recently it started losing power (RPMs oscillating up and down) while driving then dieing. Dealer sold me fuel filter & water separator filter when I explained my problem. I changed them out and bled the fuel system a few different times but the tractor still will not start since changing the filters. The fuel in the water separator drops down to the bottom of the top section when I crank the engine. After I stop, it slowly refills after a couple of minutes. I suppose I can make sure the gasket is seated properly, but I first wonder what is happening to all that fuel. It is not leaking anywhere. Also, could the outlet from the tank to the fuel line have been clogged from the beginning and it that my first problem to solve.

 

[mdhughes]

Check to see what kind of flow you get if you take the hose going to the water separator off. If it doesn't flow good, then there is something in the tank that is blocking the output port.

Make sure you have something that you can clamp the hose with to stop the flow.

 

[North Idaho Wolfman]

The Fuel system is a loop what the system doesn't use for the motor is returned to the tank.

Note: DO NOT open or disconnect any of the high pressure fuel lines, Either hard or soft lines.

Remove the line that feeds the separator (red) you should get good flow.
If you don't get good flow you have something in the tank restricting flow.
If you get good flow, Re connect, remove the output line (blue) you should get good flow.
If you don't get good flow, pull the input fitting and check for obstruction.
If you get good flow move on to next picture.

Pull the bleeder (green) and turn the key to run, do not crank or start it.
You should get good flow.
If you don't get flow, the electric lift pump electrical feed or the pump itself has failed.
If you get good flow, replace bleeder and leave it cracked and leave the key in the on position for several min to bleed the system.

 

[Hempstock]

I pulled off the line going into the fuel filter and there is no gas coming out. How do I unobstruct the tank?

 

[fried1765]

I pulled off the line going into the fuel filter and there is no gas coming out. How do I unobstruct the tank?

Seems normal,........ with "no gas coming out"

 

[Russell King]

“Gas” is the wrong word to use for “diesel fuel”

If there is no fuel coming out that is a problem that needs to be addressed.

I think you may have some sort of biological or trash problem in the tank. Can you remove the line out of the fuel tank and see if there is any fuel there? Can you drain the tank and put fresh fuel in it and treat it for biological contamination?

 

[old and tired]

I pulled off the line going into the fuel filter and there is no gas coming out. How do I un-obstruct the tank?

Just going to offer constructive advice about forums in general... The more information you can give us, the better the chance we can help you. For starters, Your profile only lists "Kabota B series" Which Kubota model is it? Our replies depend a lot on the model, If it's a B3350 - you would have LOTS of problems we might be able to list!!!

Actually, asking your question attached to an old thread already limits the number of people that might have an answer for you... Don't worry about the 2 questions that you've already asked... START a new Thread/Post in "Service, Repair & Maintenance" forum, List your tractor model #, and a little about the issue... "fuel problems"...

If you don't want to do that... this problem has been covered a few times, you can read other solutions here online. BUT if you do have a B3350, you have plenty of reading to do!!!

Lastly, you most likely have Algae in the tank, you can add a diesel fuel biocide, you might have a leaf that can cover the outlet, Let us know does the engine run then cuts off? Right now, use compress air to blow back into the tank and see if you get flow... and how much? Trickle or pours out? good luck!!

 

[Hempstock]

Just going to offer constructive advice about forums in general... The more information you can give us, the better the chance we can help you. For starters, Your profile only lists "Kabota B series" Which Kubota model is it? Our replies depend a lot on the model, If it's a B3350 - you would have LOTS of problems we might be able to list!!!

Actually, asking your question attached to an old thread already limits the number of people that might have an answer for you... Don't worry about the 2 questions that you've already asked... START a new Thread/Post in "Service, Repair & Maintenance" forum, List your tractor model #, and a little about the issue... "fuel problems"...

If you don't want to do that... this problem has been covered a few times, you can read other solutions here online. BUT if you do have a B3350, you have plenty of reading to do!!!

Lastly, you most likely have Algae in the tank, you can add a diesel fuel biocide, you might have a leaf that can cover the outlet, Let us know does the engine run then cuts off? Right now, use compress air to blow back into the tank and see if you get flow... and how much? Trickle or pours out? good luck!!

 

[Hempstock]

It's a Kabota L3902. It's definitely trash in tank. About every 1-2 fill up or 10-15 hours it gets blocked. I pull off line from fuel grommet at bottom of the tank and physically, by mouth, blow into the tank by attaching a short tube to fuel grommet. It clears and immediately starts flowing. I completely drained deisel fuel tank twice and have run clear deisel thru to try to wash out. Can I remove the grommet and would I then be able to see the screen at bottom of tank or is it part of the grommet. I am trying to avoid removing the tank.

 

[old and tired]

Looks like the grommet just goes into the tank... and filtering is done at the fuel filter... You can look up parts diagrams at Messick's website. https://www.messicks.com/catalogs/kubota/l3902hst/fuel-system/a10101-fuel-tank

So no chance with algae in the tank clogging the opening since it so new of a tractor? You use fresh fuel and not from an old bulk tank?

 

[Hempstock]

Tank has grommet exiting tank. That's clogged. Fuel filter is clean and is after grommet, so clog is not there. Clog is in tank before grommet or possibly inside grommet. Diagram doesn't show where the screen is. I was told there is a screen somewhere between grommet and tank. Is it partner the grommet? And if I pop the grommet out isn't that just then a hole leading to the bottom of the tank. Why not just pop out and thoroughly flush wirh deisel instead of pulling the tank to do the same. My main question is could there be something inside the grommet that keeps falling back into it to block it.

 

[old and tired]

...I was told there is a screen somewhere between grommet and tank....

Who told you this? It's just that I've never heard of a screen in the tank... there are several threads about junk in fuel tanks that blocks the outlet. Don't know of one that was fixed without removing the tank (which is a major PITA job).

There was one guy recently that wanted to try and run a shop-vac into the tank to clear the junk out... (after emptying out the fuel) but like a fair amount of posters, he never came back to report success or failure.

As you can see, the tank is an odd shape and would most likely need to be flushed a few times to make sure to get all the junk out. Mental Note to self - - Don't let junk get into the tank!!!!

Algae on the other hand, can grow in the tank and clog the outlet... {Insert icon of beating a dead horse}