Rough Running BX

[15pbc]

I have essentially the same problem as the OP. 2006(?) BX1850D stored under cover. Always fueled with Mobil from a local station. Symptoms: running ok then RPM's drop; sometimes just a bit, sometimes until I'm sure its going to stall and quickly disengage the PTO and let up on the wheel pedal. In every case it doesn't actually stall but after a few seconds is (apparently) back to normal. I was getting the work done but always nervous it was going to die and I would have to tow it back to the barn.

After reading the excellent info from the OP I got buckets ready under the 1850D and pulled off the fuel hose after the electric pump...barely any flow. Pulled off the hose after the primary fuel filter....barely any flow. Pulled off the hose feeding the primary fuel filter....decent flow, but way less that I expected from a nearly full tank. Then I blew air into the hose and presto, good flow. I was using a couple small pails to fill 5 gal pails and I had wiped all of them clean before starting. After the first couple pails were in the bucket I looked in the bucket and the bottom was loaded with small black debris. After it had been emptied and dried a bit I could shake the primary fuel filter and it sounded like a baby's rattle. I have not seen any debris other than the black stuff which looks like rust flakes.

I went through the very non-service-friendly work to get to the fuel sender (I never did get the mower height knob off even after beating it upwards with a mini-sledge) and what to my wondering eyes should appear but the exact same rust on the sender rheostat housing that OP discovered. And the extensive rust I saw is AFTER all the debris in the bucket had fallen off it. I have to believe the issue here is simply bad fuel senders. Consider: I use no additives, just fresh name brand Diesel that I store inside the barn in yellow 5 gal purpose-made cans. The tractor is inside the barn so there is not the "tank sitting in the bright sun" issue that produces water in aircraft fuel tanks. I'm located about 25 miles West of Boston so salt air isn't a factor. The fact is I've had occasion to pull senders out of many machines WAY older than this thing (maybe 300 hrs) like stationary gensets, trucks, cars, planes, etc and I've NEVER seen rust /corrosion on one even in the same ballpark as this.

How would we know if there was a recall on these? A service bulletin? (Does Kubota even do recalls or service bulletins?) It could be that there are hundreds of these situations and the dealers just happily sell a new sender and filters and add few hundred bucks in labor plus trailering to and from the shop as I suspect few owners of this class of tractor do significant (or any) work on them themselves.

I welcome any comments.

 

[ultrarunner]

Sending unit corrosion is a known issue.

I had to drain and blow the lines to get good flow once.

Since then, I keep the tank full at all times...

Not sure if it makes a difference... just have not had the problem come back.... yet!

 

[15pbc]

Keeping the tank full is a good idea but we shouldn't have to, especially as Kubota doesn't say to or even suggest it.

I know the rust/corrosion is known however there was a lot of comment about an additive possibly being a culprit or if it was just a very odd occurrence. I'm saying that even with other circumstances I have the exact same result. I called my dealer and they looked up the p/n for a s/b or any comment at all about the design and there was none. So presumably Kubota is making the exact same item today.

I showed the sender to some mechanics at work and all were amazed that such damage could be caused inside a tank.

I have attached 4 pics, the orange thing is the Home Depot bucket of fuel that was totally clean so you can see all the crap that came out of the tank. The other 3 are of the sender, note the holes rusted right through the cover.

 

[ultrarunner]

Looks much worse than mine... almost like a ticking time bomb as far as the fuel system is concerned.

 

[platimer]

Thanks for this information. We're dealing with this problem right now. We just finished replacing both fuel filters. The temp is about -4 degrees, and we need to clear out a LOT of snow before the next big snowstorm hits Tuesday. But after the filters were replaced, it acted like it would run okay. After about five minutes of work time it started doing the same thing again, where the power went up and down for no apparent reason. We're going to put some kind of fuel conditioner that will dry up the water in case that is the problem. We did notice one of the filters we took out was sort of plugged up. I'm hoping it's not the tank. This is also a fairly new machine, I think it's about 2 or 3 years old. It's the BX2350 model. Any other suggestions are appreciated.

 

[15pbc]

If you didn't already I'd drain the tank into a pail (I used a couple small pails to move the fuel from the hose going into the first filter to the 5 gal pail). Otherwise the rust will just clog the filter again. Also if you drain the tank and the pail isn't all filled with rust bits you'll know it's something else.

When you take off the tank hose from the first filter leave the fuel filler cap on at first. If no fuel comes out and when you take off the cap fuel pisses out fast you'll know the (way too complicated) vent in the cap is blocked.

Good luck.

PS a good friend of mine, the long time Director of Projection at Radio City Music Hall is from Streator.

 

[15pbc]

I tried and tried to get Kubota to send me a replacement sender for free or at least to admit there was something wrong with a sender housing rusting to pieces in a few years while other nearby steel parts (the float arm) have no rust at all.

No sender, no admission that a sender rusting to bits is anything other than my own fault for not immediately filling the tank to the very tip top after each use.

Gee, if that's really required wouldn't it be great if it was mentioned in the manual?

But they did send me a mesh Kubota ball cap; great for snow blowing.

 

[platimer]

Thanks for that info. I'll go tell the guy who's working on it about this. By the way, the fuel tank is plastic on this one, so it can't be rust.

 

[15pbc]

Yeah all the fuel tanks are plastic I think, the rust all comes from the box around the fuel sender. It flakes and flakes and makes way more rust than I would have thought.
Some other guys have found plastic bits left over from making the tank too.
And of course stuff could have fallen in the filler hole. I may make a filter for it out of aluminum window screen.

 

[platimer]

We seem to have the BX running good again (Yay!). Was advised that pouring new fuel into a cold tank was a bad idea immediately preceding the start of this trouble. The tank has been near empty and the air temp had been running negative zero for the better part of two or three weeks, so it was a very cold tank. Anyway, for the fix to this problem he put a small heater up behind the tractor in the barn and warmed up the tank. Then poured Kerosene (# 2 Fuel) into the tank. It has been working like a champ for the past three hours and we have most of the snow cleared again, just in time for a new storm to come in tomorrow or Wednesday. So, to recap what we did, we changed both fuel filters, put fuel stabilizer in, heated the fuel tank before starting the engine, and when warm, added Kerosene. Hoping that it will work for us now for a good long time. I will be sure to ask the guy to fill the tank when he puts it back up in the shed tonight.