BX stalls around 1/2 tank on sloping ground

[91diesel]

Does anyone else have this issue? I live on pretty steep terrain (one of the reasons I went with a bx23s instead of a B series). My tractor will run fine but sputter and stall out (sometimes) with the tank at about 1/2 way (+/- some). Usually it's on steep terrain, but also happened the other day on flat ground. The fix for it is removing the fuel line from the engine side of the fuel pump, turning on the ignition, fuel will pump out great, hook line back up and run start the tractor. Obviously it seems like it's going into vapor lock so I pulled apart the vent in the fuel cap. This seemed to help for a while, but I'm also not sure that I actually ran it down below 1/2 tank. I'm working in snowy/icy conditions so there's always a possibility of the vent getting clogged again (I just cleaned it out again). I've also tried loosening/removing the fuel cap when this is happening (to no effect). To get the tractor started again, I have to remove the fuel line and then it'll run fine for an hour or so. Anyone else having this issue? It's kind of annoying having to keep the tractor topped off all the time so that it won't stall at an inopportune moment.

 

[PoTreeBoy]

Does it matter which side is low?

 

[BigG]

I would change the fuel filter, there may be 2 on your tractor. Then run some "fuel conditioner" to remove any type of water.

 

[pjoh784350]

Does anyone else have this issue? I live on pretty steep terrain (one of the reasons I went with a bx23s instead of a B series). My tractor will run fine but sputter and stall out (sometimes) with the tank at about 1/2 way (+/- some). Usually it's on steep terrain, but also happened the other day on flat ground. The fix for it is removing the fuel line from the engine side of the fuel pump, turning on the ignition, fuel will pump out great, hook line back up and run start the tractor. Obviously it seems like it's going into vapor lock so I pulled apart the vent in the fuel cap. This seemed to help for a while, but I'm also not sure that I actually ran it down below 1/2 tank. I'm working in snowy/icy conditions so there's always a possibility of the vent getting clogged again (I just cleaned it out again). I've also tried loosening/removing the fuel cap when this is happening (to no effect). To get the tractor started again, I have to remove the fuel line and then it'll run fine for an hour or so. Anyone else having this issue? It's kind of annoying having to keep the tractor topped off all the time so that it won't stall at an inopportune moment.

The BX I believe has a saddle tank (think saddle bags). On steep slopes all fuel will drain from one side into the other and then is trapped on that side. That is not the fuel pick up side.

 

[85Hokie]

without turning the key ALL the way ...........are you hearing the ticking of the fuel pump?

Gravity will feed the injector pump, but once fuel it low , it will not - listen carefully for the fuel pump ticking .... no ticking...... fuel pump is bad!

 

[91diesel]

The sputtering and stalling happens on my driveway when going up it (so left and right side of the tractor are relatively even). It's not a filter issue (and I've replaced one already anyway) because the tractor will run for hours with a full tank with no issue.
I'm mostly convinced it's the fuel cap vent getting iced up causing a vapor lock issue, but I find it weird that taking the cap off doesn't 'fix' the sputtering relatively immediately (or at all). But if I disconnect the fuel line, turn on the ignition so the fuel pump pumps out fuel, then re-attach it....... it's an 'instant' fix to the problem. The biggest pita part of it is that disconnecting the fuel line by the injection pump won't do the trick, 95% of the time I have to disconnect it at the fuel pump end. I've also found that if I was to leave the tractor for a couple hours and come back it'll fire right up and run like nothing happened (most of the time walking away from it for a couple hours isn't an option).
So I'm just putting this out there seeing if anyone else has had this issue and if I definitively find what's causing the issue, I'll make sure to share it.

 

[GreensvilleJay]

BTDT, sad to sad, but 99.44% sure you have a 'something' in the tank blocking the spigot where the fuel come out. In my case it was a small donut shaped piece of plastic that eventually wedged itself into the spigot. Cure was to remove tank, clean it out, reinstall tank. I took 3 easy days to do the job, afterwards asked dealer, they'd only charge me 3hr labour(+-350).
It's not a hard job to do, 2 extra hands is nice though as seat assy is HEAVY and AWKWARD. Tank is kinda 3 chamgered and dark. LED flashlight helps but I never saw the 'culprit' until it got flushed out with water. That was 2 years ago.benn 100% since then. I did add a filter screen to the tank. Some here use a 'cold coffee mason jar filter, I went to $store.

 

[Dave_eng]

I am with 85hokie on the "lift" pump. Also the easier thing to check out.

Dave

 

[tinkerwitheverything]

Yup leaning towards fuel pump as well. Being that if you leave it alone and come back its good to go. Pump gets hot stops working properly then cools off and works ????

 

[RCW]

Lift pump could be the issue.

Also, from my experience, the fuel gauge on a BX is terribly inaccurate. When mine hits half full, I can put 4-5 gallons in it.

I refill as soon as it gets off full, and it’ll take 3 gallons.

Tank is only 6.5 gallons.

I’m wondering if you’re just plain running out of fuel…..that’s the easiest thing to check first. Would be my first stop.

Good luck!

 

[ACDII]

First thing, it isn't vapor lock. That is when fuel vaporizes in very hot lines, and is usually related to carburetors which have low pressure, 5-7 PSI lines, and happens right at the carb.

Diesel doesn't vaporize in such a way to cause this, BUT what is possible is the fuel pump is bad. The diaphragm may be weak or have a tiny hole in it that is sucking in air as the pressure into the pump is reduced as the level in the tank drops. Since it is gravity fed, the weight of a full tank will be greater than that of half a tank, so higher inlet pressures at the pump.

As the inlet pressure drops, and think about this, as you go up or down hill, the fuel will always seek level, so the pressure to the pump is reduced even more as the fuel moves away from the pickup at the bottom of the tank. As that pressure is reduced, the pump can no longer draw fuel, and is probably cavitating which produces air bubbles. Purging the line at the pump removes the air bubbles, equalizes the pressures, and it starts working again.

The pump is probably on it's last legs, so that is what I would replace.

 

[91diesel]

Lift pump could be the issue.

Also, from my experience, the fuel gauge on a BX is terribly inaccurate. When mine hits half full, I can put 4-5 gallons in it.

I refill as soon as it gets off full, and it’ll take 3 gallons.

Tank is only 6.5 gallons.

I’m wondering if you’re just plain running out of fuel…..that’s the easiest thing to check first. Would be my first stop.

Good luck!

I've wondered this as well, but like I said, I can detach the fuel line, turn the ignition on to pump fuel, reconnect it and she'll start up and run. (This immediate sequence of events leads me to generally rule out the lift pump and tank exit being the problem) The last time the tractor did this I put more fuel in it, but it was only around 3.5-4 gal? It didn't empty a 5 gal container I had anyway. BTW, I put the fuel in it after 'fixing' the issue and driving it up the driveway.
Again, pretty sure it's a vapor lock issue from icing up the tank vent in the fuel cap. I'm wondering if mine has particularly tight or wrong clearances or something. This morning I was trying to figure out why removing the cap when it starts sputtering doesn't fix it right away. Also why a fuel line on the bottom of the tractor must be undone and NOT at the injection pump (in this case, it's literally the same line just opposite ends!). I think it has to do with the fuel level in the tank......

(I think) this is what is happening. The tank stops venting and with a full tank this is no issue due to there's no vacuum yet because there's no free space in the tank to create it. When it gets enough fuel out to create a vacuum the fuel pump will start to collapse the rubber line coming from the tank and the tractor will start sputtering and trying to stall. Taking off the fuel cap at this point doesn't stop it due to the collapsed fuel line and 3 gallons or so of fuel sitting on top of it. I think disconnecting at the injection pump is the same problem in that it's as high as the outlet of the fuel tank. Only disconnecting it on the bottom of the tractor releases the fuel line collapse and that's why it will 'instantly' fix the issue. Anyway, that's my working theory. It may not hold water in a vacuum theory class........ I may just pull the rubber check valve out of the fuel cap vent and put the little plastic cap back on. That should for sure get rid of any venting issues. I'll keep everyone posted. Although with most of the last snow dump taken care of, I might have to make something up to run it through that much fuel. Plus I'll want to verify over time.

 

[91diesel]

ACDII, just read your reply. Yeah that's a possibility. I brought that up to the Kubota dealership (tractor isn't even a year old). I have definitely seen icing buildup on the vent (and yes, calling this a vacuum lock is a better description) and clearing that off seemed to fix the problem. Icing of course here and now can be a constant ongoing issue. The issue with troubleshooting this is that from a full tank, I can run this thing 4 hours at high throttle and only get to just above 3/4 of a tank.

 

[ACDII]

Yeah, unless bush hogging, my B2410 will sit at full all day long, so I know what you mean. Problem I see with your theory is that it takes a LOT of vacuum to collapse the fuel hoses, so much so that you would hear a huge sucking sound as you removed the cap. It would also show in the side walls of the tank, so maybe if/when it does it again, see if you can see the tank sides and if they flex any when you remove the cap. It could be a head pressure issue as well causing pump lock up, but the part about which end of the line gets removed is the puzzling factor.

 

[GreensvilleJay]

EASY way to PROVE your 'vapour lock' idea... crack the tank cap couple of turns and drive around.
Or rubber band some plastic bag ove rthe filler spout, poke a few holes in it.

if it runs then the caps at fault, if it dies NOT the cap..'gremlins in the tank'.

 

[bronc71]

I am expecting a situation similar to happen to me. I was pouring in some stabilizer into tank and the paper seal that’s normally glued into bottle cap fell in and sank to bottom. Figured it will block my fuel line eventually, and when I really need it to work. It’s not a horrible job to pull the tank, it is a lot of parts to remove, but my guess is something is in your tank too.

 

[RCW]

I've wondered this as well, but like I said, I can detach the fuel line, turn the ignition on to pump fuel, reconnect it and she'll start up and run. (This immediate sequence of events leads me to generally rule out the lift pump and tank exit being the problem) The last time the tractor did this I put more fuel in it, but it was only around 3.5-4 gal?

Did you detach the fuel line in the exact steep spot the engine stumbled, or did you drive it to a level spot?

"Steep" means a lot of different things to different folks. I drive my BX on some steep spots. Those are indeed steep. I wouldn't do that without the tank near-full. Same reasons I suspect your issue. But I'm guessing.

Like others said, if you think the tank is getting into a vacuum, loosen the cap or take it off. Problem should be solved if the vent is the issue.

I really doubt the fuel cap is the issue.

The ability to put 4 gallons in the tank means it's much less than "Half-full" according to the gauge. It's a 6.5 gallon tank, so you're at 1/4- 1/3, and on a steep slope besides.....

Many times, if you suck a tank dry, you suck in crap into the fuel system....the number of times here on OTT have said "I ran my tractor out of fuel, and now it doesn't run right...."

The fuel tanks on many modern tractors are a funky shape.

There could be an obstruction in the tank to the outlet, but start with the simple stuff. That's the way I was taught.

Absent a cap vent problem, I would recommend you don't run to half-full, because it obviously doesn't work....

Also, keeping a fuel tank near-full always helps limit the amount of water than can be introduced into the fuel system.

As temps rise/fall, the fuel will expand/contract, thus introducing atmospheric humidity into your fuel tank.

Moisture in your fuel tank can also contribute to the production of algae and bacteria. Both can clog up a diesel fuel system like Grant took Richmond!

I see you're in Alaska. Don't know how many hours/week you put on, but what you're doing may be inviting problems now or in the future.

My best advice is keep your fuel tank full for several reasons.

If it runs right while full, why dick around with this problem? Period.

A few weeks ago, I said to my doctor that "my shoulder really hurts when I do this. "

He said don't do that....

 

[91diesel]

RCW, 'don't do that' haha, great advice of course. It's more if I spend a couple hours on one driveway, then a couple more on another driveway, then want to do a little touch up on mine and it stalls..... Or if I start on someone's driveway at 3/4 tank and it stalls (that time it was on 'flat' ground when it stalled).
And yes, I'm detaching the fuel line at the exact spot, re-attaching it and driving away from the same spot.
It has stalled at what is a 1/2 tank and slightly above before. The 3.5-4 gal fill up was just the last time.

 

[Whatscooking]

Floater in the tank.

 

[RalphVa]

Did you get some nights down at or below 10 F? I had wax globs come out solution on my JD 4010 (like a 2019E if made today). It would only run at or just above idle. The globs were mostly blocking the outlet from the fuel tank. Had to siphon the tank and then fish out the globs with a remote 3 finger fish tool. High fuel level would have helped to push fuel past the globs, and they might "swim" around a bit around the outlet of the tank. Wax would actually float because it is lighter than the fluid it came from. So, might not happen right away. (I used to work in lube oil industry in dewaxing of lube oil is why I I know this stuff).

It was the only time I'd ever used off road diesel, strangely enough.