Kubota B26 Fuel Nozzle Leak

[Ylr]

Hi Everyone -

I have a Kubota B26 tractor that is leaking fuel at the injector nozzle base where it threads to the head. It’s pooling at base of injector specially at high rpm. I have no idea what it could be anymore and hoping someone can give me some advice on what could be causing this problem.

what I have done so far:
Purchased new nozzle and replace it. New part came with crush washers and heat shield. (Oem part from Kubota dealer)

I got a Kubota repair manual that said to torque the injector to 38 pounds. Which I did.

I also replaced the glow plugs just in case it was leaking from there as well.

i cleaned everything up to see if any leaks happened again and it’s still leaking/pooling at the base of the injector nozzle.

that being said, I replaced the other 2 injectors and those are fine no leaks. I did the same with all three. I don’t understand why the one keeps leaking.

if anyone has any suggestions would greatly appreciate it!
Thank you

 

[Ylr]

this is a picture of the injector that’s leaking.

 

[North Idaho Wolfman]

These are the common leak points:

 

[dholt53]

These are the common leak points:
View attachment 122080

Did you put the soft washer on the bottom of the lnjector body?

 

[North Idaho Wolfman]

Did you put the soft washer on the bottom of the lnjector body?

Not having the bottom crush washer installed wouldn't cause it to puddle fuel, it would be a compression leak and it would blow air, not fuel.

 

[Runs With Scissors]

Just to clarify.

Was this "fuel pooling" problem the reason you changed it in the first place, or is this a "new problem" ?

 

[Ylr]

Just to clarify.

Was this "fuel pooling" problem the reason you changed it in the first place, or is this a "new problem" ?

yes, this is the reason why I changed the injector and it’s still having the same problem. Originally I looked at the diagram and assumed it was the crush washer at the base of the injector but I replaced it with a factory Kubota crush washer and the problem still there.
The rest of the injector feels/looks dry to the touch at the points circled on the picture above.

 

[Ylr]

Did you put the soft washer on the bottom of the lnjector body?

Yes, I put a factory crush washer right above the heat shield that came with the new injector.

those 2 pieces came new with the new injector. I also replace the fuel overflow line and installed new crush washer on them as well.

 

[Ylr]

So I think I might have figured out what’s going on. I dried up all the mess and took a video so I can see how long it takes to pool up. Well I can see the (fuel) which I thought was diesel it might be oil coming out of the back of the head cover and slowly flowing down to the injector base and pooling there. I took some pictures to see if you guys think it’s the same thing before I take it all apart.

 

[fried1765]

So I think I might have figured out what’s going on. I dried up all the mess and took a video so I can see how long it takes to pool up. Well I can see the (fuel) which I thought was diesel it might be oil coming out of the back of the head cover and slowly flowing down to the injector base and pooling there. I took some pictures to see if you guys think it’s the same thing before I take it all apart.

View attachment 122120 View attachment 122121

Seems quite likely.

 

[Russell King]

You should be able to smell the difference between motor oil and diesel fuel

Take a clean paper towel and soak up some of the liquid from the puddle and smell the towel.

Compare to diesel fuel smell from your tractor’s fuel tank.

 

[Ylr]

You should be able to smell the difference between motor oil and diesel fuel

Take a clean paper towel and soak up some of the liquid from the puddle and smell the towel.

Compare to diesel fuel smell from your tractor’s fuel tank.

I did that and it is oil. I’m going to get the new seal on Monday and replace it to see if it stops the leak. I will post whether it stops or not.

 

[Russell King]

Ok that is good news.

I assume by seal you mean the valve cover gasket? You may want to apply some sort of gasket sealer to the new gasket on both sides. I would use something that is non-hardening like Permatex #2 or Halomar. The dealer may have a better recommendation.

Did you try to tighten the bolts on the valve cover up and see if that stopped the leak?

 

[whitetiger]

The rocker cover seal is a rubber strip that inserts into a groove around the bottom of the rocker cover, almost like an o-ring seal.
Do not use any type of sealer on the seal other than a very light coat of grease or oil.

 

[Russell King]

Than

The rocker cover seal is a rubber strip that inserts into a groove around the bottom of the rocker cover, almost like an o-ring seal.
Do not use any type of sealer on the seal other than a very light coat of grease or oil.

Thanks for clarifying that there is no need for sealant on the valve cover gasket.

 

[Ylr]

The rocker cover seal is a rubber strip that inserts into a groove around the bottom of the rocker cover, almost like an o-ring seal.
Do not use any type of sealer on the seal other than a very light coat of grease or oil.

Thanks everyone for all the suggestions and recommendations. I really appreciate the help!

I removed the cover and yes it was the gasket that was broken and one of the bolts was loose as well. I replaced it and just run a bit of oil on the rubber gasket and put everything back together and no more leaks!!!
Here is a picture so everyone can see what the problem was.

again thank you so much everyone!

 

[North Idaho Wolfman]

Well someone was in there before and used RTV, and that looks like it pushed the gasket out.
This is why you only oil the gasket and not put sealer on it.

 

[Runs With Scissors]

Glad you got it fixed, and thanks for the update.