Bleeding the fuel lines, bet this have never been asked before

flyidaho

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Feb 28, 2017
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On my D1103 3 cylinder engine on my Jacobsen mower, I recently needed to replace the main fuel line from the tank to the pump. The engine ran fine before BTW. This involved removing the fuel tank to get at one hose clamp. So I replaced the line, installed the fuel tank, and filled it about half way up, and it fired right off. But (of course) after maybe 30 seconds it puked out, and this engine does not have a primer pump like my old Mercedes 190D or another older Kubota 3 banger I used to own.

I have a vague idea that I need to crack all three of the injector lines on top of the cylinders, and crank the engine until fuel is visible, but not sure if I should do that one at a time or all at once, or if it matters. I feel foolish asking this as this a classic diesel issue, but it's been so long since I have run one dry i need a reminder. I'm going back out to the shop now and trying cracking all three lines and cranking, and will report back.
 

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AllDodge

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I would loosen them all until fuel shows up, then close down 2 and try some more.

Some of those motors have an electric fuel pump and can be run by turning the key between run and start. This would be a place where the glow plugs of such would be used
 

Dave_eng

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Look for a special fitting on the injection pump. I am not certain on your particular engine but many have such a feature to allow air to get out of the pump quickly.

A close up photo of the pump would help.

The attached page is not your engine but provided to get you looking

When bleeding the injectors have the throttle wide open. I prefer to do one injector at a time but that is just my way.

Dave
 

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North Idaho Wolfman

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Look for a lever on the side of the lift pump, some of the jacobson's had that feature on their units. ;)
 

flyidaho

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I cracked all three at once, and cranked until a bit of spurting took place, but also still air bubbles (in retrospect) were visible. Then the battery got low. After tightening them back up, it fired up but ran crappy. Then some visitors stopped by, with a box of wine, and the work was put on hold for the day!

Next move is to do it again, but more, with a charger on the battery, shouldn't be an issue I'd bet.
 

flyidaho

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Well I didn't expect this: I bled the heck out of it, and all I can get is very rough running, obviously not getting proper fuel flow. Keeping in mind it ran great before I pulled the old fuel line and the fuel tank. bled it again, and again, and it just doesn't get any better.

Here's a picture of the injection pump. What caught my eye was the "fitting" on the lower right, marked with a little red paint it looks like. I will try pushing on it with a tool, a finger pushed didn't move it, not sure what it is?
 

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North Idaho Wolfman

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Pull the line going to the injection pump, it should have full flow to it if it doesn't then something before it is plugged up, or failed. ;)
 

D2Cat

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Most folk are not patient enough when getting the air out of the fuel system. Be sure to have throttle full on. Lines loose at injectors. Turn engine over in 15-20 second burst. Wait 30-40 seconds before attempting again or you can over heat the starter. Probably take at least 5-6 cranking attempts to get clear fuel. When one line has no bubbles, tighten it. Then repeat the process with the second etc.
 

flyidaho

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Since my last post, I took a lunch break, and when I went back out to the shop, it fired up and ran fine! Part of the issue may have been, probably, a splice I made in the feed line, new 3/8" to old 5/16" hose, all I had at the time and I was trying to not make a 30 mile round trip to town to get some new stuff. I had a seep at the barbed coupler, tightened the clamps even more and it dried up. Mowed the runway just now and see it's seeping again, so one new continuous length of the correct size fuel line will easily solve that. I get carried away sometimes trying to get things down with what I have on hand, part of the fin I guess but now and then I regret it, ha ha.
 

D2Cat

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But now, with all that experience, you can get the new hose on and have no problems getting it going!!

When working on the fuel systems, whenever you can, always have the engine warmed up before starting to open the fuel system. It just make it easier to turn over and fire quicker, requiring less battery power.
 

lugbolt

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Most Kubota engines don't need the nozzle lines to be loosened to bleed the system. I ain't never seen one that didn't have a bleeder valve on the pump inlet as NIH spoke of; but I ain't been around many reefer units and that sorta thing either (that use Kubota engines). Actually I've seen more damage done by loosening the injector lines than by using the correct bleeder.
 

flyidaho

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I replaced the fuel line and put a new inline filter in, and for whatever reason, this time there was no problems, it started and ran perfect from the get go. The Jacobsen mower now has no leaks, best of all! Finding a new ignition is the last thing I need to do, the old one is trashed and requires removing a jumper cable to shut her down. If I can't find the exact same switch I may just go with toggles as I really don't need the key function. This thing really moves out, faster then I want to go as my ground is not that smooth, and it has the power to mow fine while hauling butt, I can see why they use them commercially.