Fuel starvation

[firefighter206]

Hello guys, I have a 17 L6060 hst with a cab, it has 350 hours on it. At random times, I will be running the tractor and all the sudden the engine will begin to surge and clatter, the rpm will drop to almost dead, sit for a minute then come back to where I have it set, sometimes it will just die suddenly, usually it will crank rite back up, sometimes it refuses to crank and I have to pull the fuel line off behind the fuel pump and blow through the separator back into the tank, usually it cranks immediately and will run for random times, sometimes 5-10 minutes or until I’m finished with the project I’m doing. I have pulled the crossover hose under the tractor off and dumped both tanks of fuel into a tank flushing both tanks, got lots of trash and debris out, thought my problem was definitely solved then it began to do it again, so this time I bypassed the fuel water separator thinking. It had an obstruction it it somewhere, still does it, I have noticed that when it dies, I can pull the line off the fuel lift pump on the front side and fuel just bubbles out of the line and strong in my opinion, but it still stumps me as to why it only runs after blowing back behind the pump into the tank, please help, it’s just about drive me crazy, I’ve took it to the dealer, they kept it a week or 2, told me it was ready, I went and got it, ran good, then after a while, here it goes again, the picture I’m posting is what I got out of the tank after the dealer said they cleaned the tanks. Thank You

 

[Roadworthy]

It sounds like you may have crud collecting at the output of your fuel tank. Blowing back into the line blows the crud away from the output until fuel flow moves it back. You may need to drain and clean your tank and begin using an algicide to kill further algae build up.

 

[woodman55]

There is a box that Kubota calls "tank (reserve fuel)" tied into the supply, it is after the electric fuel pump and check valve. You may want to check that. Also the engine draws fuel from the left tank, which has a pick up screen in it. That would also be something to remove and check.

Please let us know how you make out.

 

[firefighter206]

It sounds like you may have crud collecting at the output of your fuel tank. Blowing back into the line blows the crud away from the output until fuel flow moves it back. You may need to drain and clean your tank and begin using an algicide to kill further algae build up.

I did drain both tanks, in the bucket with fuel in the picture is what I got out of it, I did it until nothing else came out and was a clean flush, did this on both tanks

 

[firefighter206]

There is a box that Kubota calls "tank (reserve fuel)" tied into the supply, it is after the electric fuel pump and check valve. You may want to check that. Also the engine draws fuel from the left tank, which has a pick up screen in it. That would also be something to remove and check.

Please let us know how you make out.

I did purchase a camera from harbor freight this July weekend (25% off) to try and see my pickup tubes in the tank and see if I missed something on the 5 flushes I did, I will try and find this screen as well

 

[GreensvilleJay]

re: 'flushing'. hopefully you turned the tanks upside down, lefty,righty ,ALL sorts of 'gyrations', using hot water several times. A quick once or twice...'looks OK' won't be enough. As you've got algea in there, it can be stuck to the top of the tank..
Getting a camera is a GREAT idea, as it's best to actually SEE how 'clean' really is.

 

[firefighter206]

Update guy, sorry for a long delay, I work 2 jobs, don’t have much down time, I have drained the tanks again, no trash came out, hopefully I got it the first time, put my camera up in the tanks, could not see anything, blew everything from the fuel filter back to the tank, couldn’t find nothing, replaced the fuel filter with a wix, let it run for over an hour, no clattering, no missing, then I pulled it out of the carport, ran it again for another hour while I greased it, still ran as should, will get to run it more Monday hopefully, we will see what happens, Thank You all for your help and input, greatly appreciated

 

[dvcochran]

First, make certain your fuel tank vents are not stopped up. Common problem. Especially since there was evidence of trash in the tanks, you need to replace or at least blow out and thoroughly visualize the fuel lines from tanks to injector pump. Many of us have been down the road where you cannot see the trash stuck in a fuel line from just looking at the end of the line. Also, ditch the spring clamps and get good screw down clamps so that you know you are not sucking air.

 

[firefighter206]

Well I tried it today, ran good for about 30 minutes, barely got it back to the house, driving running good at 1500 rpm then it drops to 2-300 or just goes dead, spin spin spin finally cranks back up but clatters and surges in and out as it gets fuel, not sure wth to do now, totally frustrating

 

[JerryMT]

Well I tried it today, ran good for about 30 minutes, barely got it back to the house, driving running good at 1500 rpm then it drops to 2-300 or just goes dead, spin spin spin finally cranks back up but clatters and surges in and out as it gets fuel, not sure wth to do now, totally frustrating

All that crap and corruption has not been removed from the fuel delivery system. If it was, you wouldn't have a problem keeping it running. And remember, just because it idles for hours is no reason to believe that the fuel restriction is gone. It doesn't take much fuel to idle an engine so you can have a partial blockage that lets enough fuel to idle but not enough for full load operation. That crud can get into the filter head passages and changing the filter or blowing back from the fuel filter inlet to the tank won't get it out. If there is something between the tank and fuel filter inlet and you blow back to the tank, whatever was in there goes back into the tank.

If this were my tractor, I'd start from the tank outlet and see how much fuel flows to the filter inlet. If it comes out like a cow peein' on a flat rock, then that line is clear. Remove you filter and see if fuel flows through the filter head like the aforementioned cow. If it does than that component is clear. If it dribbles or is intermittent, then you found your problem. Continue on. When you get to the lift pump, if it's mechanical, crank the engine. If it's electric, turn on the key. Same thing. Is the fuel flow strong or is it weak and /or intermittent? (Some lift pumps have an internal screen that can clog.) Lift pumps can also fail. What about the solenoid on you fuel cutoff at the IP? Is it holding the fuel cutoff open?.

Go through the fuel delivery system component by component systematically and you will find the problem.
Good Luck.

 

[firefighter206]

Ok guys, had a great day, got to drive the tractor and do lots of yard work, after about 30 minutes, it started struggling and dying, usually at this point, I’d turn the key off, get off and back blow through the lines to the tank, this time I left the key on so the fuel pump would continue trying, I started at the reserve port, no fuel, just bubbles, I moved down to the check valve, bubble, no fuel, I then removed the line between the fuel water separator and the pump, it was dry, so I took the line off from the tank to the fuel water separator and bypassed the separator and come from the tank straight to the pump, primed up ran at 1500 while I ate supper, no problems, got back on it, worked for almost 2 hours with no problems at 1500 driving around in the yard using the grapple to move limbs and just general clean up, when I was just about convinced I had fixed the problem, it began to die again, no fuel at the intake of the pump, when I took the line off, a few drops ran out, within a few seconds, I plugged it back up to the pump and it primed rite up and went on till I parked it, this time, at least I know my problem is somewhere between my tank and where it comes from out under my cab to the intake of the pump, as bad as I hate to, I’m going to have to figure out how to drop them tanks from under that cab and shake whatever is in there out or if it’s my intake hose sucking to the bottom or side of the tank, figure out how to fix that. Standby for more updates, it will be next week before I get another day off to work on it, we will see, I’ve attached a few pictures of what I did so far.

 

[South 40]

Hey Firefighter,

OK so it's possible you have one of several issues here, first is that there is something floating around in the tans that is blocking the port to the fuel line, from the pics it seems you don't have a shut off at the tank, but I wonder if there is still a pickup screen on top of the tank nipple that is clogging up.

The other possibility is the line from the tank either has some crap stuck inside or is too soft and the suction pump is collapsing the line.

When you blow back thru the line you are just moving the obstruction just enough to let the fuel flow until it flaps back over and blocks the line again, or you release the vacuum from the line, either way I suggest you replace the entire rubber fuel line and find a way to look inside the tank and see if there is a screen just above where the fuel exits the tank and if there might be a leaf or something in there that blows away the floats back over the exit point/screen.

It's may have only a few hours on it, but you never know how it was treated/stored before you got it, any trash, algae, or no telling what else could be floating around inside the tank.

Buy Clean fuel and keep it clean.

Cheers
Samantha

P.S. Buy one of these https://www.amazon.com/gp/product/B07R5D6W1S/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 before you drop them tanks they are cheap and oh so handy to have around for so many things, with that you should be able to have a look inside the tank and see if there is anything around the exit point.

 

[JerryMT]

Ok guys, had a great day, got to drive the tractor and do lots of yard work, after about 30 minutes, it started struggling and dying, usually at this point, I’d turn the key off, get off and back blow through the lines to the tank, this time I left the key on so the fuel pump would continue trying, I started at the reserve port, no fuel, just bubbles, I moved down to the check valve, bubble, no fuel, I then removed the line between the fuel water separator and the pump, it was dry, so I took the line off from the tank to the fuel water separator and bypassed the separator and come from the tank straight to the pump, primed up ran at 1500 while I ate supper, no problems, got back on it, worked for almost 2 hours with no problems at 1500 driving around in the yard using the grapple to move limbs and just general clean up, when I was just about convinced I had fixed the problem, it began to die again, no fuel at the intake of the pump, when I took the line off, a few drops ran out, within a few seconds, I plugged it back up to the pump and it primed rite up and went on till I parked it, this time, at least I know my problem is somewhere between my tank and where it comes from out under my cab to the intake of the pump, as bad as I hate to, I’m going to have to figure out how to drop them tanks from under that cab and shake whatever is in there out or if it’s my intake hose sucking to the bottom or side of the tank, figure out how to fix that. Standby for more updates, it will be next week before I get another day off to work on it, we will see, I’ve attached a few pictures of what I did so far. View attachment 86788 View attachment 86785 View attachment 86786 View attachment 86787 View attachment 86788 View attachment 86785 View attachment 86786 View attachment 86787 View attachment 86788

You're on the right track! Is there a way to remove the outlet from the fuel tank? You ought to be able to use a wire to clear up what's in there and flush the crap out of the tank.
When you get this straightened out, consider two fuel management strategies; 1) Keep the tank as full as possible between uses. This will reduce water condensation which allows bacteria to live in the fuel tank; 2) Treat you fuel with a biocide to kill any bacteria in your tank.

 

[firefighter206]

Ok guys, been extremely busy with 2 jobs and family and holidays and life but I’ve got great news and need a little input, was finally able Saturday 12-10-22 to spend the entire Saturday working on this problem, I was able to completely take the tank out from under the tractor and give it a thorough inspection and shaking lol, the line from the fuel pump to take is clear and free from any blockages, once I removed the fuel level reader and pickup tube assembly and shined my light into one hole while looking in the other, I seen a small object about the size of a 50 cent piece, I will attach pictures, not sure WTH this is or how it even got into my fuel tank much less how it made it over into the left fuel tank but that’s what I found, I removed it, shook the tank again and verified there is nothing in the tank but fuel remanence, I re installed everything, cranked and ran about an hour and a half with no hiccups, was late, didn’t get to drive it around much to see if it’s going to act up any more but I’m almost 100% sure I found the problem, more to follow and please help me identify what this is that was in the tank, looks like some type of plastic, Thank You all

 

[firefighter206]

Hey Firefighter,

OK so it's possible you have one of several issues here, first is that there is something floating around in the tans that is blocking the port to the fuel line, from the pics it seems you don't have a shut off at the tank, but I wonder if there is still a pickup screen on top of the tank nipple that is clogging up.

The other possibility is the line from the tank either has some crap stuck inside or is too soft and the suction pump is collapsing the line.

When you blow back thru the line you are just moving the obstruction just enough to let the fuel flow until it flaps back over and blocks the line again, or you release the vacuum from the line, either way I suggest you replace the entire rubber fuel line and find a way to look inside the tank and see if there is a screen just above where the fuel exits the tank and if there might be a leaf or something in there that blows away the floats back over the exit point/screen.

It's may have only a few hours on it, but you never know how it was treated/stored before you got it, any trash, algae, or no telling what else could be floating around inside the tank.

Buy Clean fuel and keep it clean.

Cheers
Samantha

P.S. Buy one of these https://www.amazon.com/gp/product/B07R5D6W1S/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 before you drop them tanks they are cheap and oh so handy to have around for so many things, with that you should be able to have a look inside the tank and see if there is anything around the exit point.

I did purchase one of the caneras from harbor freight, used it to verify the inside of the tank was completely 100% free of any debris, Thank You

 

[firefighter206]

You're on the right track! Is there a way to remove the outlet from the fuel tank? You ought to be able to use a wire to clear up what's in there and flush the crap out of the tank.
When you get this straightened out, consider two fuel management strategies; 1) Keep the tank as full as possible between uses. This will reduce water condensation which allows bacteria to live in the fuel tank; 2) Treat you fuel with a biocide to kill any bacteria in your tank.

Thank You, I think we finally solved this 3 year old mystery

 

[PoTreeBoy]

Ok guys, been extremely busy with 2 jobs and family and holidays and life but I’ve got great news and need a little input, was finally able Saturday 12-10-22 to spend the entire Saturday working on this problem, I was able to completely take the tank out from under the tractor and give it a thorough inspection and shaking lol, the line from the fuel pump to take is clear and free from any blockages, once I removed the fuel level reader and pickup tube assembly and shined my light into one hole while looking in the other, I seen a small object about the size of a 50 cent piece, I will attach pictures, not sure WTH this is or how it even got into my fuel tank much less how it made it over into the left fuel tank but that’s what I found, I removed it, shook the tank again and verified there is nothing in the tank but fuel remanence, I re installed everything, cranked and ran about an hour and a half with no hiccups, was late, didn’t get to drive it around much to see if it’s going to act up any more but I’m almost 100% sure I found the problem, more to follow and please help me identify what this is that was in the tank, looks like some type of plastic, Thank You all

Looks like the check valve flapper out of the crossover line.

 

[woodman55]

Looks like the check valve flapper out of the crossover line.

I agree, looks like the flapper from the one way check valve in the cross over tube.

 

[woodman55]

Looks like the check valve flapper out of the crossover line.

I agree.

Item 60.

 

[firefighter206]

Kiss my grits I think ya

Looks like the check valve flapper out of the crossover line.

you are absolutely rite, Thank You