B7800 fuel pump

A. Cox · Jan 10, 2011

Hello All,

I'm a definite newbie, both here and too deisel engines!! My b7800 was running perfectly. I came back from moving a bunch of dirt one day, shut it off and have not been able to get it started since. It will crank over. I have power to the glow plugs, and have replaced the glow plugs. The fuel stop solenoid will pull in and stay in when the key is in the run position. However I do not have fuel at any of the injectors..nor do I have fuel coming out of the mechincal fuel pump. I have replaced the fuel filter, and fuel will gravitly feed up to the mechical fuel pump. But when I take the line off the downstream side no fuel will pump out if I crank the engine...leading me to believe the fuel pump is shot.

To replace this pump is there anything special I have to do...ie does the #1 cylnder have to be at TDC or do I just unbolt it, clean up the matting surface, replace the gasket and bolt a new one on?

I'd sure appreciate any help or thoughts!!

Aaron

A. Cox · Jan 11, 2011

Bump...

Well I have a new fuel pump arriving today....if I can figure out how to get it installed I'll post an update here...

If anyone has any advice I'd sure appreciate it!!

Thanks
Aaron

stuart · Jan 11, 2011

The service manuals I have here do not cover the B7800, but I can't see how the different B series engines would be that much different (but I have been wrong a few times). What I have covers B5100-B7100
I can e-mail you the page on fuel pump replacement if you are interested. Pm me with you e-mail address.

Stuart

A. Cox · Jan 11, 2011

Stuart...

I talked to the guys at the parts counter and they said just pull the old one out and put in the new one....So I did. Now I have fuel pumping to the injector pump, but none reaching the injectors. I checked the fuel shut off solonoid and it seems like its working correctly.

So now I'm at a loss as to what to check next...bummer.

Thanks for the offer for the email!!

Aaron

Theekillerbee · Jan 11, 2011

Make sure you bleed EVERYTHING down stream of the pump. Any air in the system will lock it up. Gotta bleed every single injector at the injector. Sometimes it takes a time or two of bleeding to get all the stinking air out of the lines.

A. Cox · Jan 12, 2011

thekillerbee...Thanks for the advice. I'll make sure to rebleed everthing again today. But I'm not really getting any fuel out of the lines...should it be squirting out? I sure wish I had got it running yesterday!! We got over two feet of snow last night and its still snowing

I am running out of room to pile it and the fel would have been nice to have......oh well....

thanks again!!

aaron

Theekillerbee · Jan 12, 2011

You should have decent pressure at the injector pump, then after that, she gets pretty powerful. Don't take the lines all the way apart, just crack the fittings enough to let the fuel leak out. Don't be tempted to put your finger next to the fittings to check for leaks either! That stuff is bad mojo if it is squirted into your body. Sometimes the bleeding has to be repeated a few times to get all the injectors working properly. I had an old Ford TLB that got ran out of fuel a couple of times...talk about a pain! Learned my lesson the hard way, don't run a friggin' diesel out of fuel!

A. Cox · Jan 13, 2011

Thanks so much for the advice fellows...I really appreciate it!! I didn't get a chance to work on the tractor at all yesterday. I was out plowing all day (on a 1953 international low boy tractor of all things...she's slow and little but eventually gets the jobs done) I hope to get out and try again today. I figured the deisel should be under a bunch of pressure when it comes out of those fittings.

I really really aprectiate all the help! Thanks

aaron

A. Cox · Jan 17, 2011

Well all, its been a few days but I owe everone a huge THANK YOU....I finally took the lines off right at the injector pump and made sure I had fuel comming out there, then broke each one at the injectors and finally got fuel to come out there...and it started right up.

So thanks...

of course heres the next issue...

The tractor ran great for about an hour then shut off...just like if i turned off the key...So i checked the fuel shut off solnoid. when i bench tested it the plunger would pull in. So i stuck it back in the tractor...won't start. I try to start her again and hear two clicks...one when the key is in the run postion and then it clicks again when i turn the key to start. So i wonder to myself if i have some sort of ignition problem. I took and ran a jumper wire from the battery to the two leads on the solnoid...tractor started right up and ran fine.

Arg.....So i'm guessing i probably have an isue with the ignition switch now.

But at least I can get her running and get some snow banks moved out of the way!!

I hate to ask again for help, but if anyone has any ideas i sure appreciate it.

And thanks again for helping me finally get it running!!!

aaron

alanduq · Aug 23, 2011

Same problems here but will not run quite that long. Could solenoid exhibit these problems only when hot? There must be air getting in for some reason? Also on mine there was smoke and a strange smell coming from solenoid area but no sign of burning.

CharlesB7800 · Sep 16, 2019

alanduq said:
B7800 solenoid location

I appreciated this thread BUT, I have NO IDEA where the Fuel Pump is located or where this Solenoid is located.

Is there a diagram I might look to?

North Idaho Wolfman · Sep 16, 2019

CharlesB7800 said:
I appreciated this thread BUT, I have NO IDEA where the Fuel Pump is located or where this Solenoid is located.

Is there a diagram I might look to?

You can look at all the diagrams on, https://apps.kubotausa.com/illustrated-parts/

But to get better answers you need the WSM Workshop manual you can get a copy here: http://www.kubotabooks.com/AutoInde...or Owners Manuals/&file=B2710-B2910-B7800.pdf

CharlesB7800 · Sep 17, 2019

North Idaho Wolfman said:
... diagrams on...WSM Workshop manual you can get a copy here:

Thank you for the links. The dealer came and took the tractor today. The mechanic seemed to think he'd replace the mechanical fuel pump first (he heard the solenoid click - but allowed he might need to replace that as well).

I guess I expected more of a firm diagnoses s opposed to suggesting we begin by replacing parts until the problem appears to be solved!

It just seemed too much for me to begin lest I 'fixed it' to the point where I couldn't drive it up on a trailer to get it to the dealer!

Man's got to know his limitations! Thanks for all the suggestions - I'll report back when I get the bill!

CharlesB7800 · Sep 20, 2019

Well, for nearly $700 I have a new fuel pump and should get the tractor back Tuesday. 4.5 hours of labor to change a pump that was held in place by two nuts and two hose clamps! What a racket!

North Idaho Wolfman · Sep 21, 2019

CharlesB7800 said:
Well, for nearly $700 I have a new fuel pump and should get the tractor back Tuesday. 4.5 hours of labor to change a pump that was held in place by two nuts and two hose clamps! What a racket!

Something is not adding up?

The fuel pump on that model is a $136.50, and I can change one in about 15min, little more on some models if you have to pull body panels to access the pump.

I'm not charging nearly enough!

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B7800 fuel pump

A. Cox

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stuart

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