743 Fuel Injector Pump line seeping

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Springer1

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Ok, first post !!! I was changing the glow plugs when I realized the first plug is very difficult to remove without special sockets and universal joints. So I was going to remove one of the fuel lines entering the injector pump. I couldn't get that line off without taking the first two off also. So....... I began to loosen the first fuel line entering the injector pump. It began to seep fuel, as expected. I then stepped back and realized that I could get the plug outta there without removing that line if I had the right tools.So.......I tighten that line back up, but it WONT stop seeping fuel, I have loosened and tightened it to no end, with no luck. What the heck did I do?
 

Tazza

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Did you remove the delivery valve from the pump or did you just remove the nut that holds the tube line to the delivery valve?
Is it just a small leak or is there a lot of fuel leaking out? i have in the past had to bend the tube line to get the angle just rite for it to make a good seal. You should be able to pull the nut up and sit the end of the tubeline in the delivery valve and it should sit centre, if you need to put a lot of force to hold it there you may need to bend the tube a little.
Let me know and i can take piccies of what i mean.
 

Springer1

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Did you remove the delivery valve from the pump or did you just remove the nut that holds the tube line to the delivery valve?
Is it just a small leak or is there a lot of fuel leaking out? i have in the past had to bend the tube line to get the angle just rite for it to make a good seal. You should be able to pull the nut up and sit the end of the tubeline in the delivery valve and it should sit centre, if you need to put a lot of force to hold it there you may need to bend the tube a little.
Let me know and i can take piccies of what i mean.
Thanks for your reply, its the bottom nut, so i guess the delivery valve. Its seeping out of the top of the injector pump around that nut. I would say its a small leak. If i wipe it up, it will start to bead up in a few seconds. If I try to turn the tube line nut it also turns the delivery valve nut, any suggestions would be great.
 

Tazza

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Thanks for your reply, its the bottom nut, so i guess the delivery valve. Its seeping out of the top of the injector pump around that nut. I would say its a small leak. If i wipe it up, it will start to bead up in a few seconds. If I try to turn the tube line nut it also turns the delivery valve nut, any suggestions would be great.
Ok, it seems you have loosened the delivery valve. I think these run an O ring to seal properly (its been a little while since i removed mine). If you remove the tube line then remove the delivery valve, there should be an O ring on it that you may need to replace.
If you want piccies let me know, i have a spare pump that i can take pictures of. Just don't remove any parts you don't need to, if you remove any parts lower down you can disturb its fuel delivery quantities.
 

Springer1

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Ok, it seems you have loosened the delivery valve. I think these run an O ring to seal properly (its been a little while since i removed mine). If you remove the tube line then remove the delivery valve, there should be an O ring on it that you may need to replace.
If you want piccies let me know, i have a spare pump that i can take pictures of. Just don't remove any parts you don't need to, if you remove any parts lower down you can disturb its fuel delivery quantities.
Cool man, thanks. Where can I shut off the fuel to prevent a huge mess when I do this?
 

Tazza

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Cool man, thanks. Where can I shut off the fuel to prevent a huge mess when I do this?
There is no fuel shut off on a 743. The onlly way i have found is to use a pair of vice grips on the fuel hose. Just don't set them too tight and you won't damage the hose.
 

Springer1

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There is no fuel shut off on a 743. The onlly way i have found is to use a pair of vice grips on the fuel hose. Just don't set them too tight and you won't damage the hose.
Alrighty, looks like I have a project. Thanks again Taz..
 

Tazza

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Alrighty, looks like I have a project. Thanks again Taz..
No problem, any issues or questions just yell. Like i said, i have an old pump that i have fiddled with that i can easily show you what to expect and what parts not to touch. But as long as you just remove thedelivery valve and spring you will be fine.
Good luck.
 

Springer1

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No problem, any issues or questions just yell. Like i said, i have an old pump that i have fiddled with that i can easily show you what to expect and what parts not to touch. But as long as you just remove thedelivery valve and spring you will be fine.
Good luck.
Well I have good news and bad news....... Good news: I took the line off, took the delivery nut off inspected the oring witch was in great shape, no cracks , chaffing, nothing. So I added a small oring into that 1/10 of inch space left below the stock oring. Put it back together and NO leak !!!!!! Thanks to a semi-deep socket and some needle nose (along with a very sore finger and thumb) I got that glow plug changed out. Bad news: Start up the bobcat and theres something not right. Sounds like there is a piston not firing, cause I can hear the others firing individually, kinda like a Harley. So im assuming the spring didn't sit right on that little valve below the delivery nut :( Now im bummed, cause that has to come apart again........... Unless theres something im missing Taz?? does this sound right too you? All because of a glow plug...........
 

Tazza

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Well I have good news and bad news....... Good news: I took the line off, took the delivery nut off inspected the oring witch was in great shape, no cracks , chaffing, nothing. So I added a small oring into that 1/10 of inch space left below the stock oring. Put it back together and NO leak !!!!!! Thanks to a semi-deep socket and some needle nose (along with a very sore finger and thumb) I got that glow plug changed out. Bad news: Start up the bobcat and theres something not right. Sounds like there is a piston not firing, cause I can hear the others firing individually, kinda like a Harley. So im assuming the spring didn't sit right on that little valve below the delivery nut :( Now im bummed, cause that has to come apart again........... Unless theres something im missing Taz?? does this sound right too you? All because of a glow plug...........
How long have you run the engine? My money is on the fact the fuel has not re-filled the tube line to the injector. This is normal when you have removed a tube line or injector. The pump only squirts out a small mount of fuel every 2 revolutions.
As long as the spring and valve went back in there shouldn't be a problem.
 

Springer1

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How long have you run the engine? My money is on the fact the fuel has not re-filled the tube line to the injector. This is normal when you have removed a tube line or injector. The pump only squirts out a small mount of fuel every 2 revolutions.
As long as the spring and valve went back in there shouldn't be a problem.
cool, ill let her sit then for a bit. I couldnt stomach foolin with it any more today.
 

Tazza

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How long have you run the engine? My money is on the fact the fuel has not re-filled the tube line to the injector. This is normal when you have removed a tube line or injector. The pump only squirts out a small mount of fuel every 2 revolutions.
As long as the spring and valve went back in there shouldn't be a problem.
I'd give it a run for say a munute at decent revs and see if it clears up, if not it sounds like there is a problem with the one way valve or spring.
 

Springer1

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I'd give it a run for say a munute at decent revs and see if it clears up, if not it sounds like there is a problem with the one way valve or spring.
Well, took'er apart again and the nossle was not seated right, it was very tight in the injector nut. Cleaned all up, put back on very carefully and she now runs great. Thanks for your help. Im going to post my next issue as a new thread.
 

RobPg1967

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There is no fuel shut off on a 743. The onlly way i have found is to use a pair of vice grips on the fuel hose. Just don't set them too tight and you won't damage the hose.
Funny you mentioned the fuel shut off . Changed the fuel filter on my 743 recently - ya know I think they should have not used a glass bowl on the filter housing .... I see myself over tightening this thing one day. Anyway - I used vise grips on the fuel line also .... afterwards - I saw a pet - cock shutoff valve in the line that I could have used instead.
 

Tazza

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Funny you mentioned the fuel shut off . Changed the fuel filter on my 743 recently - ya know I think they should have not used a glass bowl on the filter housing .... I see myself over tightening this thing one day. Anyway - I used vise grips on the fuel line also .... afterwards - I saw a pet - cock shutoff valve in the line that I could have used instead.
Some have this valve hidden. Where the fuel lines go through the chassis from the fuel tank, just before the primer bulb. I didn't bother attaching one when i re-did my machine, but now i think i really should have.....
 
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