Fuel Injector External Leak? - B9200HST

[200mph]

I'm trying to help out my neighbor with his B9200HST 4wd tractor. Since the hour meter is only 3 digits plus tenths (xxx.x format) it's impossible to tell how many times it has rolled over?

In the vicinity of the fuel injectors a hard black tar like substance growing. Less than a year ago he cleaned the area real well, but never looked to see where it was originating from.

The material becomes hard but can be scraped using a screw driver. I'm guessing it is either byproducts from oil (typically uses conveniontal Rotella 15w-40) or diesel fuel.

I'm going to adjust the valves and picked up a new valve cover gasket in preparation of the task. Visually it looks like the substance is growing from the fuel injector. I know there is a seal between the head and fuel injector, but I don't see how the fuel injector body is sealed itself when referencing the parts diagrams.

1. Can a fuel injector body leak at one of the threaded joints?
2. Is the fuel injector serviceable? ie: Can the fuel injector be resealed if so?

I hate to go through the labor of removing injector to put the head to injector seal in only to have to repeat if the injector body is leaking at one of the seams. Also thinking it might be wise to replace injectors given the hours the tractor has but he is on a limited income.

Anyone experience the same or have guidance?

Thanks in advance for your help.

Sorry the picture quality is not at the quality I prefer, but this is all that he could provide.

 

[200mph]

Adjusted the valves as they were all about 0.010" or more too loose. This was the first time in 30 years they were adjusted. Of course the "packing" as Kubota likes to call the square (actually rectangular) shaped rubber o-ring was stiff and had taken a permanent set. There was no obvious leak paths across the valve cover surface though.

Cleaned up the tar like substance from around the fuel injectors as best as possible to further investigate where the fluid is coming from.

The engine was wet from cleaning off the degreaser when starting. It became very evident the fuel injectors are leaking between the threads and head. It was blowing water from around the injectors everywhere!

New injectors are being purchased from Kubota along with the injector seals.

Who knows if the injectors are ok or not, but given the age, untold hours and since they need to be removed anyway, my neighbor felt it was best to put new ones in.

Any tips for removal and installation of the injectors?

Can I assume the fuel return barb section of the injector can be removed to allow socket use?

 

[200mph]

Was able to pick up four new injectors and copper seals from local dealer, so continued with the work.

Getting the metal fuel injector tubes off of the two end cylinders went ok with no drama, but the two center ones on the injector pump were impossible to loosen up at the pump end. There was no way to prevent the fitting that attaches to the pump from spinning as the tube nuts were very tight. Wasn't certain what was under these pump fittings and didn't want to create more work/problems.

Cleaned up the injector threads/bore using a 12 gauge brass brush on a cordless drill along with dental pick, q-tips and brake clean to make certain the sealing surface was clean with no scratches.

There was clear evidence the copper washer was leaking judging by the carbon deposits. See photo and note this wasn't the worst of the four.

A bit surprised at the injector torque being only 36 ft-lbs given the thread size, but that is what the workshop manual called out.

Installed new rubber fuel lines since the originals were off and showing their 30 plus years.

Happy to say the engine sounds much smoother than what it sounded like before adjusting the valves and the new injectors. Previously there was a distinct tapping sound and a distinct knock that did not sound like it was a rod bearing. Perhaps one or more of the injectors wasn't spraying like it should.

Bottom line is my neighbor is really happy with the way it sounds and how smooth the motor is after the work.

FYI... I did try to tighten the original injector to see if it the leak would stop as kind of a science experiment. It didn't stop the leak which makes sense given how much carbon was on the copper washer and generally in the injector bore/threads. Only tried tightening them since we had the new parts in hand and was curious if it would work.

Used 17mm line wrench, 19mm wrench and 27mm deep socket for the injectors.