BX23S Engine Losing Power

[RWey56]

My 23S of 310 toatal hrs use has been running fine until today. While mowing, it seems to bog down of sorts as if something was wound around the blades. Disengaged the blade and the enging picked back up again. Cleaned pully wells on the mower deck and checked underneath; nothing binding. Started do it again a few minutes later, but noticed it was having trouble recoving RPM even with the mower disengaged. I then drove around without mowing, and it did it again.

All fluid levels are good. Cleaned the air filter, which wasn't too bad. And finished mowing a small back yard. It struggled a couple times, and again even without the load of the mower and I wasn't even rolling, so basically no load.

It's as if it's having a problem with any torque when this happens. About the only thing I can think is fuel related. Is this a fuel filter or injector issue?

Thanks for suggestions.

 

[whitetiger]

Remove the fuel hose from the bottom of the inline fuel filter on the side of the engine, hang the hose over a catch can or bottle, and turn the key switch to the run position. Do not start the engine. See how much fuel is coming out of the hose.

What you want to see is a pulsing stream, not just a trickle.
If it just trickles out, replace the lower fuel filter that is under the tractor. Pinch the hose gently between the tank and the filter self-locking pliers or hose block-off pliers to stop the fuel from just running out when you disconnect the hose from the filter.
You can check the flow from the tank by releasing the pliers on the hose to see if you have an obstruction in the fuel tank. If it has a good stream from the tank, it's most likely restricted fuel filters.

 

[RWey56]

Thanks. Instructions make perfect sense. I was unaware there were two filters.

 

[Harold Youngblood]

My 23S of 310 toatal hrs use has been running fine until today. While mowing, it seems to bog down of sorts as if something was wound around the blades. Disengaged the blade and the enging picked back up again. Cleaned pully wells on the mower deck and checked underneath; nothing binding. Started do it again a few minutes later, but noticed it was having trouble recoving RPM even with the mower disengaged. I then drove around without mowing, and it did it again.

All fluid levels are good. Cleaned the air filter, which wasn't too bad. And finished mowing a small back yard. It struggled a couple times, and again even without the load of the mower and I wasn't even rolling, so basically no load.

It's as if it's having a problem with any torque when this happens. About the only thing I can think is fuel related. Is this a fuel filter or injector issue?

Thanks for suggestions.

Mine did this last year. My fuel cap vent was stuck . I blew it with air. I suspected this in the field but being more experienced in gas engines when i loosened the cap, I didn't give it time to prime back up.
There is a little rubber flapper in it that was sticking. There are two fuel filters, one under the chassis and one under the hood by your brake pedal area

 

[RWey56]

I replaced both fuel filters and it's still losing power, and now running rough. I primed it to the point where the engine seems to be running smooth, so I assume all the air's out of the fuel line. Idles at the expected 1400 rpm, and runs smooth at higher rpm when standing still. Often, then, when reversing or going forward quickly, it gets back into the stall and runs rough as if firing poorly on one of the cylinders ... but to be honest I couldn't tell you what a poorly firing cylinder sounds like.

Harold, good idea. I'll check the cap. I've had that same issue on smaller engines too.

 

[RCW]

Possible gummed up fuel system with trash or biomass build-up.

Changing filters doesn't fix that condition. Only kicks the can down a ways.

Check @whitetiger 's response at post #2 of the thread. Will help diagnose buggered up fuel system.

 

[RWey56]

OK, I pulled the fuel line at the end, and here's the fuel flow with the key on:

Video: (2) October 10, 2023 - YouTube

Is that normal?

Also, what role does this thing serve?

 

[GreensvilleJay]

That's the solenoid that kill the fuel to the injector pump. When you turn the key off, it'll move that 'rod and arm' stuff a bit for a few seconds, then return. If it ever fails, you just manually move the arm and engine stops.....

 

[RWey56]

That's the solenoid that kill the fuel to the injector pump. When you turn the key off, it'll move that 'rod and arm' stuff a bit for a few seconds, then return. If it ever fails, you just manually move the arm and engine stops.....

Of course, it is a diesel. Duh ... on my part. I thought maybe it was some pollution control nonsense. Did you happen to take a peek at the video in my last post re fuel flow? I'm looking for any feedback as I have no idea what's "normal" for fuel pump flow.

I'm beginning to wonder if there's something plugging my tank. Watched part of a video on how to get to the tank, and no way. I'll find some other way to clean it out if that's the issue.

 

[Russell King]

Of course, it is a diesel. Duh ... on my part. I thought maybe it was some pollution control nonsense. Did you happen to take a peek at the video in my last post re fuel flow? I'm looking for any feedback as I have no idea what's "normal" for fuel pump flow.

I'm beginning to wonder if there's something plugging my tank. Watched part of a video on how to get to the tank, and no way. I'll find some other way to clean it out if that's the issue.

I have no real clue since I have never seen a good pump‘s flow but that looks to be a very limited flow out of a pump and not consistent. I have read on here that the flow should spurt out in fairly regular cadence. Read post two above for a more experienced description of the flow from a Kubota technician @whitetiger

I have also read that if the tank is full then the pump is not really needed until the tank is down to half full. But not sure what tractor that was on. You could try filling the tank and see if it runs better.

See post #2 above and do those tests and replace (both?) filters and possibly blow a bit of air back towards the tank and see what you get flowing through then.

 

[GreensvilleJay]

sorry, but 'something' is plugging the 'system'. it should be a steady, pulsated flow. If you're lucky it's just the first filter close to the tank....unlucky like me, then there's a sliver of plastic wedged IN the spigot( exit tube on the tank ). 'back blowing' MIGHT move it out BUT it'll still be 'somewhere' in the tank. being in 3 sections it's easy for 'stuff' to float around and cause you no end of grief, today, next week, an hour from now.
I tore my tank out as it was PLUGGED. You might 'win' by adding drain hose (5/16") to a bucket and 'fill/flush' the tank several time. Remove the fuel gauge and use strong LED lights to see, maybe a camera/borescope ?? When you think it's 'clean', toss some alcohol in ( winter windshield fluid) ,drain, then blow dry with compressed air. The deal is to remove ALL the water. I had the benefit of a hot summer's day to help be 100% certain, ZERO drops of water in the tank. OK, I was paranoid but I've got over 850+ hrs/ 4 years since I cleaned it out and ZERO issues. I also added a $store sink strainer to keep 'big stuff' from getting INTO the tank. some use 'cold coffee mason jar filters'....
If you decide you need to remove tank, have a pair of extra hands ready ! 1.the seat assembly is dang heavy and awkward.... 2) the 'fender/floor' pan isn't as heavy, but AWKWARD. Most knobs just pull off, cept one, the PTO lift shutoff or whatever it's really called( $7 for a new one....) Dealer said 3 hours labour...but they KNOW the sequence and tricks...it's not hard ,just a lot of steps...

 

[whitetiger]

OK, I pulled the fuel line at the end, and here's the fuel flow with the key on

That is nowhere near enough flow, and it almost looks like water rather than diesel fuel.

 

[RWey56]

Haven't had much time to work on this since last posting, but I found the problem an hour ago. Definitely a plug in the tank as blowing air back into the tank via the fuel line freed it up and it cranked right over and didn't experience any stalls. This tells me the tank needs to be cleaned out, but I'm definitely NOT pulling the tank. Too much disassembly and too little time, not to mention my auxiliary lighting is wired through the ROPS, which needs to come off when boondoggling the tank removal. I understand a BX23S is a compact tractor and they have to squeeze a lot of stuff in a small space, but things could have been done better to facilitate fuel tank servicing.

My first solution is going to involve a steady flow of low-pressure air into the tank via the fuel line to keep any debris from settling, then pump out the fuel at the same time. Add a clean gallon back, repeat. I'm also very temped to cut a 1-1/2" hole in the top of the tank just under the seat, right above the fuel line sump to act as a service port for this very issue. First need to find the right kind of fuel-resistant ( Buetel ? ) plug to put in the hole before considering that, however, and also consider how said plug will shrink/hold in sub-zero weather.

Anyway, I know the cause of the problem and can now strategize a permanent fix, which also includes a filler hole strainer which many on YouTube vids and here recommend. Given how common a problem this is, I'm really surprised Kubota doesn't include this in the tank fill hole.

 

[RWey56]

That is nowhere near enough flow, and it almost looks like water rather than diesel fuel.

It's fuel. LED shop lights skews the color.

 

[GreensvilleJay]

hmm, might be better to let the fuel drain out the spigot. If(when..) it stops due to blockage, use gonnad grippers to remove the offending blockage. the problem is the tank is in 3 sections,so it is possible for the 'blocker' to hide in one section and not come out. if you had a borscope or camera+LEDs to SEE 100% inside the tank that would help...
you and a helper can pull/clean/reinstall the tank in 3 hours. just have lots of tools, GREAT lighting and a CLEAN workspace. It's not really hard to do,just a lot of small steps.
agree Kubota should have an 'inlet fuel strainer'......

 

[RWey56]

Well, I found the problem and I'm guessing this is probably a first for most of you.

Knowing the tank was plugged, I cut an inspection/clean-out port just over the fuel sump. This involved carefully cutting a 1-1/2" hole with an exacto, which took a while. The following pic (after debris removal) is the hole plugged with rubber compression plug found at Menards for ~$3.00. After filling, it doesn't leak at all, so this is a good alternative to the 8 hours+ or so it would take to pull the tank.

Early last summer, I made a couple passes around the yard after refueling and forgetting to put on the fuel cap. Apparently, I must have brushed by the pear tree as the following pic shows what I found inside. Of all the damned places for a pear/branch to fall, where does it go? A swish shot right into the tank that would have impressed Michael Jordan. No surprise, however, as I've known for years where I fall on the bell curve of fate.

Anyway, after pumping the tank nearly dry, I was able to suction all this crap out of the tank with pump and various grabby tools. Refilled with about 1/2 gallon of diesel and repeated the suction. Small pen light showed nothing of any concern left in the sump, though I fully expect to have to replace the first fuel filter again. Not a big deal as I now know how to do that quickly.

I'm sure when I mowed without the cap, I was filling the tank got waylaid with someone else's problem for an hour or so and forgot the cap, as I have never done that before. While this remedy was certainly faster than pulling the tank, I have learned that from now on, I don't care if the house is on fire ... I will not stop the refuel until the cap is back on.

Also probably wouldn't hurt to make some sort of micro-filter insert for the filler hole in the tanks as well.

 

[RCW]

@RWey56 thanks so much for closing the loop on the problem!

Yeah, that’s a bunch of trash.

Quite a few folks use a Mr. Funnel when fueling.

Some have re-purposed coffee filter metal screens for cheap on Amazon, and can leave them right in the filler neck. They fit perfect in there.

Bet if you use the Search function for “coffee filter” you’ll find it.

I use Mr. Funnel, but have thought about one of the coffee things for my BX.

 

[DustyRusty]

When I fuel my tractor I put the fuel cap on the seat of the tractor. That way I will not forget to put it back on.

 

[NX Man]

This is exactly what is happening with my BX1850. When I pull the fuel line before the engine (the line between the second fuel filer and the engine) and turn the key to On, it shoots out and then drips out. I replaced both fuel filters and the same results. Before I go cutting into my tank or attempting to remove the tank, should I check to see if its the fuel pump? I have about 900 hour on her.

 

[GreensvilleJay]

easy test #1 ... disconnect hose tank side of lift pump, connect 5/16 hose to pail of diesel, disconnect hose after pump and connect hose back to pail. turn key on.pump should pulse pump fuel from pail and back to pail, on and on.....

easy test #2... disconnect hose at 1st filter, let gravity drain tank. if not solid flow, 'something' in tank 'spigot'. BTDT