Rough Running BX

[jcgaylord]

Rough Running BX *SOLVED*

I finally solved a problem with my BX running rough and wanted to share solution.

I trolled this forum and others the past few months to try and troubleshoot the problem. Tractor would run fine for a while (15 minutes, an hour?, 2 hours?) and then start bogging down and have no power. RPM's all over the place and almost stalling out. Sometimes sitting would help but it always returned. First time I changed both fuel filters and thought it was solved but a month later the problem returned. I read and tried everything from new diesel source, more filters, purging air, etc. but it kept returning. I noticed when it happened if I disconnected fuel line before first filter from tank it would dribble out. I tried blowing air back through line and immediately flow was like it should be (pouring out). I surmised that something was stuck in the tank outlet. So I finally got around to removing the tank today which is no fun. I did ball joints on Dodge last week and that was almost easier. Anyway after a couple hours of disassembly and taking time to thoroughly remove leaves, grass, twigs from every nook and cranny and degreasing everything I had tank off. With it empty I shook it into a white pail to see what I had in there and a lot of rust flakes came out. By a lot I would say half a teaspoon. Being a plastic tank I was curious how this could be? So I removed the fuel sender float and sure enough it was rusted and crumbling. I was shocked how bad a shape it was for a 3 year old tractor. I am glad I found the problem but am worried this could be a regular occurrence. I should also mention that before I did all this I did try and blow air out of tank. I made a tight seal with rubber glove ducktape around an air gun. I blew air and got some mist coming out of fuel line but problem still came back. After taking it apart and seeing the size of the outlet at bottom of tank, and the odd tank shape. I think it would be unlikely I would ever get all the rust flakes out. Not to mention it would keep occurring as more rust flaked off sender unit.

The picture I took is of sender and I scraped the side lightly just a couple times to show how easily it was flaking.

The disassembly is fairly straightforward. You need to take off seat, rear fender and loosen floorboard. I took floorboard off to easily clean things and do new filter. A lot of knobs and some electrical connections too. I did not do a write-up but found it pretty intuitive once I started. The only thing I will point out is the knob below seat (which controls how quickly rear three point raises/lowers) takes a lot of prying force to come off. The knob for the cutting height takes even more. I used long screwdriver as a fulcrum and pried each side slowly for a few minutes and they finally popped off.

If you have any specific questions I can try and answer them but hopefully this might save some guesswork if you are running into same problem.

some follow-up stuff:

- Forgot to mention this is for BX1850 but I think all BX's used same fuel sender.
- I have always used a diesel fuel additive to prevent gelling and algae
- The part (K2581-61370) is ~ $50 but since it was special order I decided to try and see if I could clean mine up and maybe coat with POR or something. Not that I am cheap I just am impatient. I started wire brushing lightly and once surface rust was off I found a lot of holes in outer case where rust had eaten through. Upon opening outer case I found inside was worse than outside (see pic). So no saving this part and I will wait (impatiently) for a few days.

 

[yooper jim]

Yuck ......... I think I'd invest in a new fuel sending unit. They are about $50. How could it get that rusty?

 

[oldballs]

Geez.....what could do that? If the tractor was 10-20 years old, one might expect something like that. Thanks for your investigative and knuckle knocking effort. .. ...I'll be following this thread.

 

[ultrarunner]

Great tip... thanks for posting!

 

[CHDinCT]

Intersting. Wonder if you had a few bad tanks of diesel with lots of water in it??

 

[dodge man]

That is interesting. I wonder if its corroded, and not really rusted. I can't imagine it would rust, unless it had a lot of water in the tank and it sat that way for a long time. I'm guessing that might be a part that should be made out of something different, like stainless. Good write up and it might save people a lot of time in the future.

 

[Old Coot]

Thank you for the heads up. You may be saving us a lot of trouble.

One question I would like to ask is, did you keep the tank filled through the winter? If not full, that would leave the sending unit in the air so it could rust.

I ran onto something like this with a gas powered woodchipper. I left the tank low over winter and got rust in it.

 

[mjym]

thanks man hi will check my tractor if its like that too he run good but that fuel gauge they all the same thank you mario

 

[kuboman]

Are you using biodiesel and do you keep your tank full.
Where do you live?
Is it a warm humid climate?

 

[My Hoe]

Wow...that had to have sucked to have todeal with that mystery/intermittent problem for months.

My next question is not meant to add to your troubles, but are the pumps on these tractors lubricated AT ALL by the diesel fuel itself? The reason I ask is, on older Mercedes-Benz cars, if an owner put gas in the tank by accident, it did not damage the fuel pump, because the diesel was NOT part of the pump's lubrication system. However, do the same thing on one of the '80's GM 350 diesels, and it would require a new pump, as the diesel FUEL itself was the pump's lubricant. I'm just concerned that your periodic fuel starvation hopefully did no damage to your pump. I'm sure actual techs could chime in here on that point?

Re: the degree of corrosion itself, I'm just shocked--I mean, on for a three year old machine. I too would like to know if if was your practice to leave the tank less than full often (no offense), and if you life in a damp/salty climate?

Thanks for the excellent diagnostic work, great pics and solid efforts!

To All: is it just me, or does it seem like there are more problems, lately, with (what I consider to be) rather expensive, LATE MODEL, allegedly high quality machines like these Kubotas? I'm thinking of the backhoe with the snapped off dipper stick, the brand new tractor with the "runaway" (over speeding) engine, etc.... (Don't flame me--this is something that's actually been bothering me lately--and I'm obviously an Orange fan...).

Oh! And WELCOME and GREAT FIRST POST!

Thanks again.

My Hoe

 

[My Hoe]

Wow...that had to have sucked to have todeal with that mystery/intermittent problem for months.

My next question is not meant to add to your troubles, but are the pumps on these tractors lubricated AT ALL by the diesel? The reason I ask is, on older Mercedes-Benz cars, if an owner put gas in the tank by accident, it did not damage the fuel pump, because the diesel was NOT part of the pumps lubrication system. However, do the same thing on one of the '80's GM 350 diesels, and it would require a new pump, as the diesel itself was the pump's lubricant. I'm just concerned that your periodic fuel starvation hopefully did no damage to your pump. I'm sure actual techs could chime in here on that point?

Re: the degree of corrosion itself, I'm just shocked. I too would like to know if if was your practice to leave the tank less than full often, and if you life in a damp/salty climate?

Thanks for the excellent diagnostic work, great pics and solid efforts!

Is it just me, or does it seem like there are more problems, lately, with (what I consider to be) rather expensive, but high quality machines like these Kubotas? (Don't flame me--this is something that's been bothering me lately).

Thanks again.

My Hoe

 

[AxleHub]

- Forgot to mention this is for BX1850 but I think all BX's used same fuel sender.
- I have always used a diesel fuel additive to prevent gelling and algae

I highlighted above what i would think may be a big p as rt of the problem. . . . Additives.

In some other posts, i mented how some times in vehicles when I change oil - I "flush" the motor to clean it. You can use a commercial flush. . . . . . Or you can use diesel fuel to accomplish the same thing - because fuel oil is a cleaner already. Additives typically are even more of a cleaner, and in a wrong dilution percentage, cause corrosion very quickly.

What I'm wondering is:
1. Was the additive added to the correct quantity of gallons of fuel?

2. Was the tank often run down to near empty and then allowed to sit that way (allowing additive to dry on the unit)?

Certianly I could be wrong, but more than once I've seen additives corrode metal very quickly.

Thanks for starting this thread - I will continue to watch participation. This is an important topic.

P.S. Your description and pictures reminds me alot how E85 gas effects some vehicles - because of concentration - quite corrosive.

 

[North West Farmer]

jcgaylord,

I am located in northwest Oregon and have found out the hard way that it is imperative to keep fuel tanks full if the equipment sits for a month or two during the cold winter season. If an air space is left in the tank, the exposed area my rust, but usually just a small amount if it rusts at all. The primary problem that results from the air space is moisture condensing on the exposed surfaces, resulting in water in the fuel tank that normally accumulates in the bottom of the tank.

If it freezes you end up with ice blocking the fuel line and if it is not freezing the water gets pulled into the fuel lines. In either case you end up with an engine not running until the problem is corrected.

It was quite obvious that many of the thread participants were thinking this might be the problem with your sending unit if it is located in the air space in the fuel tank. The thing that bothers me, after looking at your pictures, I have never seen anything at all close to the amount of damage exhibited on the sender parts from only being exposed to air in a partially filled tank. I have run across rust, but only light rust. After a very short period of time that sending unit looks like it has been submerged in a corrosive material of some type. If air space exposure caused that type of damage in the time you describe, you have a very strange and unusual chemical reaction going on in the air space of your tank.

If the sender has been submerged in the fuel and it has been damaged to that degree, there are some serious fuel interface problems involving the material the sending unit is composed of and/or your fuel has some chemical properties that are totally incompatible with the composition of the sending unit.
It will be very interesting to see what the reaction is of forum participants that are the professional wrench benders that work on these machines on a daily basis.

I am very glad that did not come out of one of my fuel tanks and I definitely hope there is a logical and easily solvable situation here. For me this is a real corker!

Nick, North West Farmer

 

[radioman]

uhh -- all I can say is I am shocked!. I cannot believe that it would get rusty like that. Exactly where is that sender located? I wonder if fit can be inspected from filler neck with a mirror? I am now dying to inspect mine. diesel us basically oil so I just don't see how it can rust out like that?

 

[Zick]

Wow, that is really bad looking!

Thanks for sharing though. :thumbsup:

 

[jcgaylord]

Intersting. Wonder if you had a few bad tanks of diesel with lots of water in it??

I am not sure if this was cause or not. I always buy from Hess because they are the only ones close to me that carry diesel. I use a 14 gallon tank with gravity hose and am pretty thorough as far as protecting my fuel source from contamination. Once I started having these issues I became seriously overprotective of my fuel source. I even started running a little out of hose into a catch can to clean the line before I fill my tractor.

BTW -Every now and then I use the accumulated diesel in catch can to "season" my firewood for my outdoor fire pit .

 

[jcgaylord]

That is interesting. I wonder if its corroded, and not really rusted. I can't imagine it would rust, unless it had a lot of water in the tank and it sat that way for a long time. I'm guessing that might be a part that should be made out of something different, like stainless. Good write up and it might save people a lot of time in the future.

Definitely rust. I also got the new part in and it appears ot be identical construction as what I had in there. My fingers are crossed.

 

[jcgaylord]

I did not keep it full all winter but I did use it all winter to plow and play (used it to build giant snow walls for kids to play on). I'm not really sure it is realistic to keep it full all winter or fill it after use given my own secnario and logistics. Given the part that rusted is at very top of tank shoud I be trying to keep fuel all the way up to the top?

I understand concept people are mentioning of condensation but how much space is too much? It would seem very difficult to always keep it so full there is no arispace? Maybe the intention was to keep it nearly full to limit the airspace?!

 

[jcgaylord]

I did use it all winter. I am in Troy, NY so no salty air and moderate humidity during late summer. Last winter was extra snowy so it seldom sat for more than a week. The winter before perhaps 2-3 weeks between uses. I would fill it up and then usually use it until it was a quarter tank (sometimes less) and refill it. I imagine a lot of people do the same and expect a part inside fuel tank won't rust. This winter I will defintiely try and fill it up after each use if that helps.

 

[jcgaylord]

uhh -- all I can say is I am shocked!. I cannot believe that it would get rusty like that. Exactly where is that sender located? I wonder if fit can be inspected from filler neck with a mirror? I am now dying to inspect mine. diesel us basically oil so I just don't see how it can rust out like that?

It is on opposite side of filler neck so no luck inspecting. One thing I can share is after finding the problem I did cut open the closest fuel filter (under tractor) and it had some of the smaller pieces of rust. So if you are having similiar issues I would suggest removing filter and opening it up for inspection. If you see rust particles chances are your sender is going bad.