# Kubota L2800 Fuel Injection pump



## Bertrrr (Jan 28, 2021)

This tractor runs fine then sorta falls on it's face, starts up and does it all over again
Fuel pump new, filter new, tank flushed ,
the Fuel injection pump has a " thumb wheel " valve on the side and seems to be the culprit,
Just can't figure it's purpose, there is a line that comes off it and runs back to the tank,
Maybe someone can identify it for me ?


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## Fedup (Feb 25, 2014)

I doubt the "thumb wheel" is the culprit. It's merely a bleed vent, there to allow air in the system to escape. It's only opened for maintenance purposes, like when you replace fuel filters, mess up and run it out of fuel, or some other fuel related component needs/gets attention. It should be opened when you need to bleed the system, turned clockwise until it seats closed, then left alone. If you have a fuel related problem, my guess is that's not it. 

My suggestion. Look at the fuel filter base. If there's a small line on the top going to tank or return circuit, find something and pinch that hose flat so nothing can pass through it. A couple flat washers and a pair of vise grips works. Then start and run the tractor as always and see what changes.


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## Bertrrr (Jan 28, 2021)

Thanks , I'll look further into this today, yesterday it was running like normal and this valve was closed, 
I opened it and it began faltering , after I messed with it ,it seemed to go away,


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## Bertrrr (Jan 28, 2021)

Well I found the line your speaking of, machine was running decent then it started to surge / falter and began slowing down little by little, I pinched that vent line off like you suggested but it didn't seem to make a difference. 
There are 2 of these lines that run to the top of the fuel tank, the other one seems to come from the rear of the injection pump. 
Still looking for ideas,


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## Fedup (Feb 25, 2014)

That was a shot in the dark suggestion. I know a number of tractors that use that style filter assembly, and on more than one occasion eliminating that (so called) return line has made improvements in the overall fuel supply/flow situation. If it doesn't help, no harm done. Although I'm not sure waiting for the problem to develop first is an adequate test. The idea is to eliminate flow in that line BEFORE the problem shows up. It's more a prevention thing than a cure.


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## Bertrrr (Jan 28, 2021)

Well it appears it's a fuel pump problem, I hooked up an electric fuel pump and ran the machine with no problems, while running on that pump , hooked up a fuel line to the old pump and dropped into a diesel container seeing NO fuel movement by the pump, waiting now on the replacement pump to be delivered, 
Pulled the mechanical pump off and worked the plunger by hand with a line dropped into a fuel container and it puts out nothing so hopefully it's just a bad pump


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## bill ln ne tx (4 mo ago)

Bertrrr said:


> View attachment 83622
> This tractor runs fine then sorta falls on it's face, starts up and does it all over again
> Fuel pump new, filter new, tank flushed ,
> the Fuel injection pump has a " thumb wheel " valve on the side and seems to be the culprit,
> ...


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## bill ln ne tx (4 mo ago)

If I may delve into another subject momentarily? The photo showing the fuel injection pump shows a oil cap on top of it. there is no dipstick or other source that I am aware of that indicates fill level. i asked my dealer and he said to service engine oil through it. I fill my engine oil on the valve cover access. What am I missing? I could find no reference in the service manual. Sorry for the interruption.


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## DK35vince (Jan 22, 2006)

bill ln ne tx said:


> If I may delve into another subject momentarily? The photo showing the fuel injection pump shows a oil cap on top of it. there is no dipstick or other source that I am aware of that indicates fill level. i asked my dealer and he said to service engine oil through it. I fill my engine oil on the valve cover access. What am I missing? I could find no reference in the service manual. Sorry for the interruption.


You can fill engine oil through that plug or the valve cover. Whichever is easier.
Use the dipstick to check oil level (dipstick likely on the other side of the block)


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## Old Graybeard (1 mo ago)

Dipstick is not shown in the photo but it is further down just left of the pump it was actually a little in the way while trying to remove the fuel / lift pump


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