tracking down a diesel fuel leak

[Tractor Gal]

If it's not one thing, it's something else. I feel certain that people on this board will understand that statement.

After using the BX23 for a couple of hours, I noticed a bit of smoke coming from the left side of the engine. In looking under the hood, there wasn't anything that jumped out as a problem and it wasn't like 'tons" of smoke" but just enough that I figured I'd better check. So, I removed the bonnet and lower portion with headlights...whatever that is called...and then noticed quite a collection of fuel-soaked dirt, etc. A fuel leak! I don't feel this has just occurred with the amount of debris
below the air cleaner and against the motor itself but I had not noticed any smoke prior.

As I looked more closely, it appeared that the leak was from the 3 small, rubber tubes that are connected together with a plastic T shaped connector. I purchased those 3 rubber tubes and new clips but no new T connector. It appeared OK with no clogs or leaks. After replacing the 3 tubes and clips, however, the leak has not stopped.

In looking more closely at the parts diagram, there is a small part at the base of one of the rubber tubes that is called a "screw, air bleeder," on the Messick's site as part # 15841-51360, for those so inclined. This may be the problem if that is clogged. The part is not expensive (less than $10) from Messick's but it takes 5-10 days.

But, the question is...could this really be the problem? Plus, if it is the problem, can that part be "unclogged" with reverse air compression or is a new one necessary? Maybe someone else has had similar experience.

I don't want to use this tractor much until the leak is repaired. I believe diesel fuel is not combustible but it does burn and I would prefer not
ending up injured! Thanks for any help.

Tractor Gal

 

[Russell King]

I did not look into the parts diagram but the name indicates that you may open it to bleed air out of the fuel system.

You may see if it can be tightened up to stop the leak?

 

[JimmyJazz]

The hillbilly in me says use electrical tape on the fitting until the new part arrives .

 

[Tractor Gal]

I did not look into the parts diagram but the name indicates that you may open it to bleed air out of the fuel system.

You may see if it can be tightened up to stop the leak?

I' m not sure the screw is loose...on the tractor, that is. I have plenty of loose screws. "-) I'll check that out, Russell. Thanks.

 

[Tractor Gal]

The hillbilly in me says use electrical tape on the fitting until the new part arrives .

Hillbillies, imho, are always good, JimmyJazz! I'll keep that in mind. My thinking was a clog but maybe it's a leak. Thanks for the suggestion.

 

[Henro]

”... I believe diesel fuel is not combustible but it does burn and I would prefer not ending up injured!”

I think it’s wise taking no chances about something catching on fire, especially your tractor!

I had to laugh because I think by definition something that will burn is indeed considered combustible. Actually that’s why a diesel engine along with a gasoline engine is considered an internal combustion engine!

Wish I could add something to help you… I’ll go back to my room now…

 

[Tractor Gal]

”... I believe diesel fuel is not combustible but it does burn and I would prefer not ending up injured!”

I think it’s wise taking no chances about something catching on fire, especially your tractor!

I had to laugh because I think by definition something that will burn is indeed considered combustible. Actually that’s why a diesel engine along with a gasoline engine is considered an internal combustion engine!

Wish I could add something to help you… I’ll go back to my room now…

Glad I could give you a laugh, Henro. It's hard to hide my ignorance, try as I might.

 

[Henro]

Glad I could give you a laugh, Henro. It's hard to hide my ignorance, try as I might.

Hey, before you know it you will be one of the pros here helping others with advice!

 

[D2Cat]

Can you post a couple of picture of the problem area? Might stimulate some thought!

 

[Tractor Gal]

Can you post a couple of picture of the problem area? Might stimulate some thought!

I'll do my best for now. I had put everything back together yesterday so the air cleaner and the sides of the tractor prevent a good picture. I'm not able to disassemble right now. If this doesn't help, let me know and I can do better tomorrow. In the second picture (the "taller" one) the air breather screw is at the base of that tubing. And, yes, I added zip ties to the tubing ends to see if that would help since I felt the clips were not really that tight! And, I'm not even blonde. Thanks D2Cat
.

 

[GeoHorn]

Use an aerosol electronic cleaner to spray down and dry the area... then sprinkle flour or baby powder onto the area and start ‘er up ... the exact area of the leak soon appears. The metal fittings in that area are suspect.

 

[Tractor Gal]

Use an aerosol electronic cleaner to spray down and dry the area... then sprinkle flour or baby powder onto the area and start ‘er up ... the exact area of the leak soon appears. The metal fittings in that area are suspect.

Genius, GeoHorn! I'll try it tomorrow.

TG

 

[GreensvilleJay]

I think those are the 'excess fuel returns' from the injectors back to the pump ? I looked at the Kubota Canada parts website to 'see' what they might be. On that page '020' is the 'screw,breather' that goes into the injector pump/ It could be plugged' and not allow excess fuel back into the pump, so back pressure force the fuel out at the joints.

 

[Tractor Gal]

I think those are the 'excess fuel returns' from the injectors back to the pump ? I looked at the Kubota Canada parts website to 'see' what they might be. On that page '020' is the 'screw,breather' that goes into the injector pump/ It could be plugged' and not allow excess fuel back into the pump, so back pressure force the fuel out at the joints.

That's similar to my thinking, too, Greensvillejay. I'm going to take that screw out today and look to see if there is any way to confirm a clog. The other suggestions above are good, too. I thought putting the powder on was a great idea as I have seen fuel
"perhaps" coming from the t-connector. If the breather is clogged, that would cause the excess and if it can't be expelled due to breather clog, it would have to go somewhere! I'll keep you posted. Thanks!

TG

 

[Tractor Gal]

OK...further investigation results. I am finally getting an understanding of how this fuel system works...at least, in part. The tubing located at the engine left side fuel filter goes into the injection pump which then goes through the rubber tubings I replaced and into the injectors. Excess fuel is then sent back to the tank through the overflow system which exits the injectors through a rubber tubing that is near the exhaust. That tubing runs beside and below the engine, under the chasis and back to the left rear of the tractor where the fuel tank extends.

I have checked and checked to see if fuel is going through all of those tubes from the filter to the injectors, and out to the overflow tubing by the exhaust and it flows freely. My theory at this point is that perhaps that overflow tubing back to the tank is clogged somehow and is creating a diminished flow back. When it gets "full," the flow slows down and the system backs up and begins to leak at the input tubes.

There does not appear to be any hesitation, coughing or sputtering of the engine so it must be getting the fuel?

Here's the plan, if someone could validate is OK...I am going to use the compressor to blow a bit of air through the overflow tube leaving the injectors to see if the air can get back to the tank. I would take the whole tube off but it would be quite an undertaking since it runs over and around lots of other things. I see nothing that would be damaged with a bit of pressure. If there is a clog of some kind, it would go into the tank and eventually into the filters, recently replaced, so nothing lost, as I see it.

The air bleeder screw is only to bleed air from the system and there does not appear to be that problem so that idea didn't work out...but it was a good one! I didn't put any flour/powder to check on the leak (another good idea) because I know the general vicinity which is around the tubing I just replaced and the t-connector, I just don't know why it would leak.

Thanks for listening, all. This time of year people are busy with their projects and work, so if there are no answers, I understand.

TG

 

[D2Cat]

The fuel return lines come from each injector. The rubber line goes from one to the next to the next then to the fuel tank. If you blow air in that line, remove the hose from the last injector (as the hose goes back to the tank), have the fuel cap off, and only use 5-10# of pressure. You should hear some bubbles in the fuel tank from the air, if the line is open.

You could clean off all the dripping diesel, by washing with a garden hose/nozzle. Then try to determine exactly were if fuel is coming from. It is only going to leak while the engine is running.

 

[Tractor Gal]

The fuel return lines come from each injector. The rubber line goes from one to the next to the next then to the fuel tank. If you blow air in that line, remove the hose from the last injector (as the hose goes back to the tank), have the fuel cap off, and only use 5-10# of pressure. You should hear some bubbles in the fuel tank from the air, if the line is open.

You could clean off all the dripping diesel, by washing with a garden hose/nozzle. Then try to determine exactly were if fuel is coming from. It is only going to leak while the engine is running.

OK, D2Cat, teach me something. As I look at this thing, the rubber fuel line tubing is going TO the injectors from the injection pump. Each overflow tube is metal and is continuous between all 3 glow plugs . At the end (where the muffler/exhaust is) a rubber tubing comes off that plug and goes all the way under the tractor to the tank.

I recently replaced the short rubber tubes and clips so I know those tubes are not cracked or damaged in any way. Here is a link for the diagram if you are kind enough to look to verify that I am only as crazy as I think I am. See what you think.

Fuel return line: https://www.messicks.com/ku/84754

Fuel return line between nozzles: part # 010 https://www.messicks.com/ku/84754

But...I understand...only use light pressure and listen for bubbles.

 

[kubotafreak]

Tractor gal, did you use fuel rated line? Most vacuum line cannot sustain the diesel. They will leech fuel over time.

 

[Tractor Gal]

Tractor gal, did you use fuel rated line? Most vacuum line cannot sustain the diesel. They will leech fuel over time.

I purchased the line that Messick's listed for that application. It is low pressure, I am certain, by the clips that go with the line. Thanks for the warning, though.

 

[D2Cat]

Maybe I'm all wet. I am not familiar with you specific tractor or engine. I do know that the fuel coming from the injector pump to the injectors is NOT rubber but steel. It is a high pressure like, like 2200 PSI.

The fuel return lines an not high pressure, just fuel draining back to the tank. There is a fitting at the base of the injector that has the hose barb for the return line. One injector will have only one of those hose barbs because it is only going to the next injector. That second injector will have a similar fitting but will have two hose barbs. One for the line coming from the injector in front and going to the injector to the back. The third injector will have a two hose barb fitting. One line coming from the second injector and the other side going to the fuel tank.