Yanmar 4JH5E fuel injection pump issue

[Sailing Drummer]

2012 Yanmar 4JH5E

I was changing the gear oil when I noticed an issue at the injection pump. If you look closely at the picture you can see fuel seeping from the connection between the pump and the injectors, where it’s circled. I don’t have a manual to look up the answer to my question. The question is, is this a connection that needs to be at a specific torque (if so, what torque setting) or is this a connection that just needs to be tight?

Thanks
Larry

[Wotname]

My manual isn't handy ATM but IIRC there isn't a torque figure for the injector pump nipple although there is one for the injector line nut.

Perhaps more importantly, there is a seal inside the injector pump which is presumably leaking and probably needs replacing.

[Compass790]

I dont have a 4jh5e yanmar but the corresponding part on our YSM8 injection pump called the delivery valve spring holder has a torque setting of 39.77 to 43.38 ft-lb.
There is an o-ring on that delivery valve spring holder thats screws into the pump body on ours. You dont need to buy yanmars solid gold one, any bearing supply place should have one.

You could pm Dsanduril for a 4jh5e service manual. a quick googlesearch & his name came up.
Hope that helps

[Sailing Drummer]

Wotname and Compass790

Thanks for both those comments. I did find a manual online. Haven’t had a chance to put it on the computer yet where i can see it better - only looked at it on my phone and it’s way too small to see with these old eyes! I’ll look for that seal to see if mine has one there.

Larry

[Wotname]

I have had a quick at my manual and it didn't show a breakdown of there internal sections of the IP. If the one you have found does show the internals of the IP, please let me know where you found it online as I will add it to my Yanmar library.

[Compass790]

Yes I know what you mean about trying to look at stuff on phone.
No guarantee that your delivery v/v holder has an o-ring as it looks a bit different than our Bosch/Zexel inj. pump.. I'd bet my lunch something like a 3GM30 would have an o-ring on the threads but unsure about yrs. Possible it may have a copper crush washer, you need that exploded view to be sure.
I notice some of the later manuals lack detail.

Hope, for yr sake, another of yr engine owner chimes in.


Don't know if this bloke ( guy in American) is still active on CF but you can try to PM him as he does Yanmar service & used to answer questions:ulpilot45

[Sailing Drummer]

The manual I have does not show the o-rings. Probably the same manual that Wotname has. It does show the torque for the nuts (22-25 ft-lb) but as mentioned, no torque for the nipple.

I have to look a little closer at it - not sure if the fuel is getting pushed up through the nipple because of the pressure or dripping down from the nut.

I don’t have a crowfoot wrench yet to hook up to my torque wrench so for now I’ll just use a regular wrench and “feel”. If it still seeps I’ll disconnect the lines and see if it needs an o-ring or an type seal that needs replacing.

Larry

[Scubaseas]

29 to 32ft.lb is the torque of the fuel pipe nut.

The pump nipple (Delivery Valve Retainer) torque is 25 to 29 ft.lb. There is an o-ring on the delivery valve retainer.

Clean it up with brake and parts cleaner or similar and see if the leak is from the nut or the retainer to pump. If retainer to pump send entire pump out for replacing these o-rings and to reseal unless you have some experience with FI Injection pumps and have a couple of needed tools. .

[Sailing Drummer]

Update

I just tried to tighten the nuts and also the nipples. Neither would move at all. So my guess that they are both torqued sufficiently, if not too much, already.

I don’t know how long this has been going on, maybe for a long time. I just happened to notice it because while using my flashlight on the gear oil fill hole the light passed over the pump and I noticed it was a little dirty on the outside. On closer inspection I found a very small amount of fuel by using a paper towel to wipe down the pump. After cleaning it up and then running the motor, there was the slightest amount of fuel there. No drips, just a slight sheen that I can wipe off of it.

My initial thought is to keep an eye on it. So far there has been no effect that I can notice. No air in the system. No dripping fuel. The engine starts right away and runs fine. I’d like to be able to wait until summer when we get back to our home port up north, in the Chesapeake before I pull off the fuel lines and dig more into it. I’m very handy but definitely NOT a mechanic.

What are your thoughts? If nothing changes can I wait?

[Sailing Drummer]

Originally Posted by Scubaseas

29 to 32ft.lb is the torque of the fuel pipe nut.

The pump nipple (Delivery Valve Retainer) torque is 25 to 29 ft.lb. There is an o-ring on the delivery valve retainer.

Clean it up with brake and parts cleaner or similar and see if the leak is from the nut or the retainer to pump. If retainer to pump send entire pump out for replacing these o-rings and to reseal unless you have some experience with FI Injection pumps and have a couple of needed tools. .

Scubaseas

I was writing my update while you were responding so I didn’t see your response until now.

I will keep trying to figure out which is leaking. I need to be more methodical in how I do that. If it is the DVR I will not attempt to do that myself. I’ve never “messed around” with the pump and wouldn’t try without having someone experienced with me.

Is there any issue with waiting since this is an extremely small amount that I’m seeing?

Larry

[Scubaseas]

The DVR relies on the o-ring to seal. How loose or tight will not effect the o-ring sealing.
To torque a nut properly you first need to loosen it. then tighten it to proper torque.

If you have a slow leak or seepage from the DVR I would not worry about it. The more you use it the better it may get. Or not. It is not likely to fail suddenly or catastrophically.

[Sailing Drummer]

Scuaseas

Thanks. Yes I did know that about torque but at the same time I forgot all about it!!! I will continue to keep an eye on it and try to figure out where it’s coming from. It’s more of a slow seeping than a leak. Hopefully I can leave it alone until I get back up north.

Larry

[Jack C]

Best diagram is the parts manual, not the service manual. Part manual has an exploded diagram that numbers and names each part.

[Sailing Drummer]

Originally Posted by Jack C

Best diagram is the parts manual, not the service manual. Part manual has an exploded diagram that numbers and names each part.

Thank you. No o-ring or similar showing with the pipe nut, but between the nipple and pump there are a few things.

[Compass790]

Originally Posted by Scubaseas

The DVR relies on the o-ring to seal. How loose or tight will not effect the o-ring sealing.
To torque a nut properly you first need to loosen it. then tighten it to proper torque.

If you have a slow leak or seepage from the DVR I would not worry about it. The more you use it the better it may get. Or not. It is not likely to fail suddenly or catastrophically.

Yes +1 for this.
I use toilet paper wrapped around offending parts to trace fuel leaks after cleaning them. Might be difficult in your application.


The torque is to apply the correct pressure to the sealing face between the delivery v/v & plunger & barrel in our Injection pump. Also to the copper crush washer under the barrel but your pump may differ.



If you take it to a diesel injection place rather than Yanmar it would likely cost a lot less.