B7100 fuel injector?

[NicO]

If the engine is running, it's easy to figure out which injector is affected. Simply loosen the line fitting on top of the injector, one cylinder at a time. If the engine rpm drops, then that injector is doing something. If it doesn't, you found the bad one. Now leave it cracked open for a few moments to ensure it is fully bled. If the rpm picks up when you retighten it then you "fixed" it.

Sometimes the little buggers just want more bleeding.

Unfortunately the engine wont start, or stay running if we start it by spraying fuel in air intake.

Randomly/counter intuitively though the closest the engine get to starting on it own stream is when we loosen the nut of the line to one of the injectors from the pump (to attempt to bleed), then when we tighten it again it goes back to struggling. This particular line was struggling to get a flow of fuel. We see bubbles at this location on b the other two lines.

This is making us think there is something wrong with the diaphragm at the bottom of the pump.

 

[NicO]

First look up inside of the filter housing as these filters are know for the metal ends popping off the filters when they are old and getting stuck in the top of the filter housing.
P/N 15231-43560 all of them have 2 metal capped ends.

As far as what your experiencing, sounds like you have a pump issue, not something you want to deal with without the proper tools and equipment to test and repair it.

FYI: You won't get any pressure out of the fuel injection lines, they need a closed system to build pressure.

When you remove the Injection pump, remove and save all of the shims under the pump as that set the timing.
You will simply reuse these shims with the rebuilt pump and the timing will be right.

I use Oregon Fuel Injection for all of my pump rebuilds.
I would also suggest you replace all three injectors while your at it.
They sell those too.
And test all there glow plugs.

 

[NicO]

First look up inside of the filter housing as these filters are know for the metal ends popping off the filters when they are old and getting stuck in the top of the filter housing.
P/N 15231-43560 all of them have 2 metal capped ends.

As far as what your experiencing, sounds like you have a pump issue, not something you want to deal with without the proper tools and equipment to test and repair it.

FYI: You won't get any pressure out of the fuel injection lines, they need a closed system to build pressure.

When you remove the Injection pump, remove and save all of the shims under the pump as that set the timing.
You will simply reuse these shims with the rebuilt pump and the timing will be right.

I use Oregon Fuel Injection for all of my pump rebuilds.
I would also suggest you replace all three injectors while your at it.
They sell those too.
And test all there glow plugs.

Also…do you happen to have parts numbers for the fuel pump and injectors and glow plugs pls.

Do you have any parts diagrams too. No idea where to find this sort of info. Also looking for parts diagram & numbers for that little diaphragm at the bottom of the pump (if it’s separate from the pump one).
Or can you point me in the right direction. I contacted Oregon fuel injection and they asked me to find the Part numbers.

 

[North Idaho Wolfman]

Thanks for your great reply. That makes sense about the filter, I’ll pull it back out and swap it.

What sort of specialist tools do you need to re-build the pump? I wish there was a youtube vid on it (cough cough ).

We haven’t yet inspected the diaphragm part of the pump (not sure what it’s called) to see if that is the issue, would this make sense that it could be this is there was constantly air getting beyond the pump towards the injectors, and not being able to evenly push fuel to each of the injectors.

There is no diaphragm in the injection pump.
Now there is one in the lift pump but that wouldn't put air in the injector lines.

A diagram / picture of the pump is not going to help you rebuild it, or even understand how it works.
There is a little in the WSM on it but not on rebuilding it.
In order to rebuild the pump you need test equipment to check the wear on the pump parts and to test it's pressures.

You can get the WSM ( aka service manual) at https://www.kubotabooks.com/
You can look at the parts diagram on:

Kubota Tractor Corporation - Illustrated Parts List

- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams

apps.kubotausa.com

 

[North Idaho Wolfman]

Injection pump PN
15381-51010

Either number for the injectors
15271-53020
19202-53020

 

[NicO]

Injection pump PN
15381-51010

Either number for the injectors
15271-53020
19202-53020

thanks very much for the part numbers. I now have the correct fuel filter so I could progress with more troubleshooting. So I disconnected the hose from the lift pump to the fuel injection pump and cranked the engine to see how much fuel was being pushed through (obviously with high hopes that the issue lies with the lift pump rather than the fuel pump). I made a video but I can’t post it so I’ve taken a series of stills from the video to illustrate the fuel flow/pumping at its peak out of the pipe (hopefully they are in the order I intended)…does this look like the correct volume of fuel from the lift pump?

 

[North Idaho Wolfman]

thanks very much for the part numbers. I now have the correct fuel filter so I could progress with more troubleshooting. So I disconnected the hose from the lift pump to the fuel injection pump and cranked the engine to see how much fuel was being pushed through (obviously with high hopes that the issue lies with the lift pump rather than the fuel pump). I made a video but I can’t post it so I’ve taken a series of stills from the video to illustrate the fuel flow/pumping at its peak out of the pipe (hopefully they are in the order I intended)…does this look like the correct volume of fuel from the lift pump?

If your getting pulsed flow then it's working.
Amount of flow will be really low.

 

[NicO]

If your getting pulsed flow then it's working.
Amount of flow will be really low.

So I disconnected the high pressure lines from the fuel pump to the injectors. One of the connections at the fuel pump was very tight to undo (had to be the bloody middle one, the most difficult to get a good grip on with the wrench) but that one and one of the others (so 2 of 3) had rusty looking fuel sitting in them

I cranked the engine and basically nothing was happening except some movement/bubbling but definitely no ‘fountain’ like I was expecting,
however, when I backed off the bleed screw it was squirting out of there at some pressure, not sure if that is the result of the lift pump or not. Basically not looking great for the injection pump!
what would cause rusty looking fuel. Water been sitting in there somewhere for a while??

 

[North Idaho Wolfman]

So I disconnected the high pressure lines from the fuel pump to the injectors. One of the connections at the fuel pump was very tight to undo (had to be the bloody middle one, the most difficult to get a good grip on with the wrench) but that one and one of the others (so 2 of 3) had rusty looking fuel sitting in them

I cranked the engine and basically nothing was happening except some movement/bubbling but definitely no ‘fountain’ like I was expecting,
however, when I backed off the bleed screw it was squirting out of there at some pressure, not sure if that is the result of the lift pump or not. Basically not looking great for the injection pump!
what would cause rusty looking fuel. Water been sitting in there somewhere for a while??

Yea water will do that.
It needs a rebuild or replacement.

 

[NicO]

So a couple more questions...I’m suing the kubota parts finder tool and im struggling to identify the lift pump. The closest thing that looks like it is called the ”assay breather” would that be the one. Seems like an odd name. I’m thinking if there is rust in the fuel pump then there is likely same issue in the lift pump so was planning on ordering a rebuild kit for that As that looks like an easy enough job, would you agree?

next question.…if i take off the injection pump myself to send off or to rebuild myself, is there a specific way to do so whereby avoiding messing up the timing. I assume I would receive the part back from the specialists ready to go but can i just drop it back in and the timing will pick up where it left off. I know you mentioned keeping hold of the shims, is that all, or do i need the engine to be in a specific point in its cycle?

cheers

 

[North Idaho Wolfman]

So a couple more questions...I’m suing the kubota parts finder tool and im struggling to identify the lift pump. The closest thing that looks like it is called the ”assay breather” would that be the one. Seems like an odd name. I’m thinking if there is rust in the fuel pump then there is likely same issue in the lift pump so was planning on ordering a rebuild kit for that As that looks like an easy enough job, would you agree?

next question.…if i take off the injection pump myself to send off or to rebuild myself, is there a specific way to do so whereby avoiding messing up the timing. I assume I would receive the part back from the specialists ready to go but can i just drop it back in and the timing will pick up where it left off. I know you mentioned keeping hold of the shims, is that all, or do i need the engine to be in a specific point in its cycle?

cheers

Yes keeping the shims is all that is required for it to be back in time.
Nothing changes on the lift pump, it's the engine block that changes so the shims match the block not the pump.
The engine can be at any rotation, it does not matter.

Don't rebuild the lift pump just replace it.

https://www.amazon.com/15381-52030-Kubota-B1550D-B1550HST-D-B1550HST/dp/B0919G13TM

 

[NicO]

Yes keeping the shims is all that is required for it to be back in time.
Nothing changes on the lift pump, it's the engine block that changes so the shims match the block not the pump.
The engine can be at any rotation, it does not matter.

Don't rebuild the lift pump just replace it.

https://www.amazon.com/15381-52030-Kubota-B1550D-B1550HST-D-B1550HST/dp/B0919G13TM

View attachment 115805

ok well that’s definitely the same part based on the picture…for some reason the manual available to me puts that part in the breather group category which threw me. The part number for mine is saying that it has perhaps been replaced by a different part number now. The quote for the replacement is quite a

Yes keeping the shims is all that is required for it to be back in time.
Nothing changes on the lift pump, it's the engine block that changes so the shims match the block not the pump.
The engine can be at any rotation, it does not matter.

Don't rebuild the lift pump just replace it.

https://www.amazon.com/15381-52030-Kubota-B1550D-B1550HST-D-B1550HST/dp/B0919G13TM

View attachment 115805

Ok that makes sense if I can find a cheaper one. That picture you sent is very helpful and confirms my confusion as my manual does lump that part into breather group for some reason.

It also suggests there is a newer part number so I’ll get hunting for that. The Amazon link you sent quotes a much cheaper version that the manual is suggesting (CAD$204.06) so I’ll check there.

My local dealer quoted $258 for each injector too and local diesel injector specialists quoted $150/injector to rebuild so I’ll hunt for cheaper versions of those too I think.

I pulled the fuel pump yesterday to take it to a local specialist and it is defiantly the problem, the slider is all seized, so we’ll see what else they find.

 

[North Idaho Wolfman]

Oregon fuel injection for injectors .
Don't get cheap eBay, Amazon, or other discount places for injectors, they are 99% junk.

 

[NicO]

Oregon fuel injection for injectors .
Don't get cheap eBay, Amazon, or other discount places for injectors, they are 99% junk.

ok yeah fair enough. The Oregon fuel injection place has a way better price for rebuilt than i can find locally. Thanks!

 

[NicO]

ok yeah fair enough. The Oregon fuel injection place has a way better price for rebuilt than i can find locally. Thanks!

So another annoying turn of events…I had a gazebo tent covering the tractor as I couldn’t get it to a proper covered shelter…so the fuel pump and fuel lines were obviously removed…now over the weekend we had lots of rain and wind and I was away and during this time the tent collapsed. I had a bunch of rags and towels covering the openings but I found them all soaked.
I’m wondering what would be the best course of action in this scenario. I’m worried water has gotten into places it definitely shouldn’t be. I’m thinking I should blow some dry heat down into the opening. Im also thinking I should thoroughly drain the oil.
Any other ideas?

 

[North Idaho Wolfman]

Drain the oil and you'll be fine.
A little moisture will not cause any lasting harm.
If there is any left over moisture in the block, it will cook off when you heat it up the first run.

 

[NicO]

Drain the oil and you'll be fine.
A little moisture will not cause any lasting harm.
If there is any left over moisture in the block, it will cook off when you heat it up the first run.

Ok wicked! Thanks for the reassurance!!

 

[NicO]

Ok wicked! Thanks for the reassurance!!

Ok so I’m rebuilding today starting with the new lift pump…I’ve noticed that the notches on the piston sleeve that give clearance for the other cams is not aligned perfectly. I have the pump the correct way up with in and out arrows in the correct placement. It looks like there is still clearance JUST!
I took the old lift pump apart to inspect it and it ‘seemed’ fine…I’m tempted to put the old one back on.

what’s your thoughts here?
Cheers

 

[North Idaho Wolfman]

Try turning the pump 180 degrees and see how the clearance looks.
If it gets better then just turn the top and middle section of the pump 180 degrees.
If it doesn't take it apart and grind the flat on the sleeve to make clearance.