Bleeding Yanmar 2qm15 injector pump

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Le Blurr
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Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Fri Nov 27, 2020 5:27 pm

I recently replaced the fuel filter and attempted to prime the system. One cylinder/line primed no problem, up to the injector, however, the rear line coming out of the injector pump won't prime. No fuel comes out with the manual lever, or when turned over with the compression levers opened. Is this a problem in the injector pump? I've looked everywhere for what could be causing this and it seems to be a unique problem. The fuel shut off appears to be fully disengaged, and the motor ran fine before changing the filter.
There is no bleed screw that I see on the injector pump for the 2qm15. Is it possible there is an air lock in the pump?

UPDATE; I figured out how to do it, so for those that don't want to read the entire threat, here it is.

Getting the injector pump to bleed on the #1 cylinder was just a matter of cracking both the delivery line nozzle, and the delivery valve spring holder that is on the top of the high pressure pump. I cracked them open, ran a good amount of fuel through it, retightened them down,and then cranked the motor over with the compression lever held down, It is now getting good even flow to both injector lines.
Last edited by Le Blurr on Mon Jan 25, 2021 6:49 am, edited 1 time in total.

Aaron
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Re: Bleeding Yanmar 2qm15 injector pump

Postby Aaron » Fri Nov 27, 2020 5:47 pm


Le Blurr
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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Sat Nov 28, 2020 10:23 pm

Thank you. I suspected it was something like that. Do you think forcing compressed air in the output side might free it up? I'm going to try the tapping while cranking first.

Aaron
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Re: Bleeding Yanmar 2qm15 injector pump

Postby Aaron » Mon Nov 30, 2020 12:36 pm

I'm not sure about the compressed air. Might be worth a try. That spring is pretty tough though so if it can't push the plunger down I don't think compressed air would either but I might be wrong.

Le Blurr
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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Thu Jan 21, 2021 5:37 pm

I got it bled and it starts, but it will only run for a few seconds, and then dies. It fires right back up though, and does the same thing. If I give it throttle, it starts to rev up, but then dies. If I don't give it any throttle, it runs slightly longer, maybe 20 seconds, before it dies.

winston
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Re: Bleeding Yanmar 2qm15 injector pump

Postby winston » Thu Jan 21, 2021 6:01 pm

Any chance you have trash in the tank partially blocking the outlet? If you take the line loose at the filter do you get a good flow of fuel.

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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Fri Jan 22, 2021 1:57 pm

There seems to be good fuel flow, the rancor was clean when I inspected it. I did put an inline electric fuel pump , and put in new injectors, during the operation. I figured that since I was at it I might as well. I'm going to take inline pump out and see if that helps. I'm also going to bleed it again just using the injection pump with the compression lever down.

winston
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Re: Bleeding Yanmar 2qm15 injector pump

Postby winston » Fri Jan 22, 2021 2:17 pm

I have no idea what an in line pump would do since the system is not designed for it. I do know if things are right it should not be needed.

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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Mon Jan 25, 2021 6:34 am

The inline pump was a big assist in bleeding the system without having to pump the lever on the lifting pump or cranking the motor. It's a flow through type electric pump so I didn't figure it would be an issue having in. It may not be, but since it is the only thing not the same as when it ran, I might as well take it out now that it has served its purpose.

I forgot to mention that getting the injector pump to bleed on the #1 cylinder was just a matter of cracking both the delivery line nozzle, and the delivery valve spring holder that is on the top of the high pressure pump. I cracked them open, ran a good amount of fuel through it, retightened them down,and then when cranked with the compression lever held down, got good flow from both sides. The electric pump will send fuel through the system to the injectors, and the return line/rail to bleed it.

I'll update when I figure out what is causing the problem

winston
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Re: Bleeding Yanmar 2qm15 injector pump

Postby winston » Mon Jan 25, 2021 6:57 am

Curious, what is this engine on?

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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Mon Jan 25, 2021 5:50 pm

It's on a sailboat. I probably should have made that clear. My boat is also in a marina 300 miles from my house, so that limits the time I have to work on it. I am reasonably confident that I will sort it out next trip.

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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Fri Jan 29, 2021 7:56 pm

Success. I ultimately had to have the injector pump rebuilt. It was leaking fuel into the crankcase. Even putting it back in though I had to bleed it using method I described above. I ran it for a couple hours today under load and it seems fine. Thanks for everyone's input.

winston
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Re: Bleeding Yanmar 2qm15 injector pump

Postby winston » Sat Jan 30, 2021 6:32 am

Thanks for the conclusion. Your thread could come in valuable for others. Glad your on the road again!

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Re: Bleeding Yanmar 2qm15 injector pump

Postby Le Blurr » Sat Jan 30, 2021 9:59 am

People do a disservice to forums like this when they come on with an issue, get people to respond to them, and then don't bother to post a resolution. In my search for an answer to this question, which has come up before, no one ever posted straight forward what the solution was. My hope is that people can do an internet search for this topic and find the answer with no problem.

Everyone on the internet said these pumps don't go bad and if they do it is a fuel issue. The fact is they do go bad, but the good news is Tractor has parts for a reasonable price.

I did learn a lot in this process. The 2qm is a good starter motor to learn about diesels, so when I step up to something newer I will at least have a good working understanding of all the components.
Thanks again for your feedback, now it's time to go abduct a few fish!


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