Stripped Injector Nut Replacement

[theway]

Cylinder 1 nut finally gave up on me and rounded off and I’m gonna have to replace it. Any tips on the easiest way? It seems like it would be tricky because it’s around the fuel line... (I’m pretty sure I can loosen it with locking pliers.)

Shown here with green circle


Thanks,
austin

[jimbunyard]

Buy a new line. Ever wondered why those lines are bent in those weird shapes? Because they're all the same length, which ensures accurate injection timing, or so I've been told...

[theway]

Originally Posted by jimbunyard

Buy a new line. Ever wondered why those lines are bent in those weird shapes? Because they're all the same length, which ensures accurate injection timing, or so I've been told...

Thanks for the reply...
Ahhh, so it comes as one unit?

Thanks, I guess it will cost a bit more now, and probably take longer to get to Australia ;-)

[jimbunyard]

Yeah, all in one.

Looks like you have a 3GM, plenty of those around, a good used one is as good as a new one, if you can find it...

[theway]

Originally Posted by jimbunyard

Yeah, all in one.

Looks like you have a 3GM, plenty of those around, a good used one is as good as a new one, if you can find it...

I’ll ask around for a nice used one, but it seems like most part have to be order, unless you’re in Melbourne.

Thanks again.

[Wotname]

Originally Posted by theway

I’ll ask around for a nice used one, but it seems like most part have to be order, unless you’re in Melbourne.

Thanks again.

Very good chance that Minards (Sydney way) would have a new or used one on their shelf.

Minards Diesel

[theway]

Originally Posted by Wotname

Very good chance that Minards (Sydney way) would have a new or used one on their shelf.



Minards Diesel

Thanks for the link, but I’m going north... planning to stop at Boatworks. Know any places between Port Macquarie and there?

[Wotname]

Originally Posted by theway

Thnankd for the link, but I’m going north... planning to stop at Boatworks. Know any places between Port Macquarie and there?

No, but give Minards a call, There is probably nothing they don't know about Yanmar (marine and industrial) and they will ship parts anywhere.

I have no affiliation with them apart from being a satisfied customer over the decades.

[theway]

Originally Posted by Wotname

No, but give Minards a call, There is probably nothing they don't know about Yanmar (marine and industrial) and they will ship parts anywhere.



I have no affiliation with them apart from being a satisfied customer over the decades.

Wonderful!
Thanks again.

[theway]

Does anyone have any advice on the process? Or know an online resource, video or article?

It’s nice to see it done first, or near from someone who’s done it before...

Thanks

[Techtool]

Replacing the line is extremely easy if you have a new or good used in your possession. Just looking at the new line will clear up any questions. If you are ever stuck and can’t get a new line assembly it is possible to remove the line with the stripped nut, take it to a welding shop and get them to build up the nut again with silver solder and re-form it to a hex shape. Just remember that when you replace the line torque the nuts on both ends to about 22 foot pounds. That’s about what a 90 pound woman could do with a 6 inch wrench... or at least my 90 pound woman does

[jimbunyard]

Pretty basic, cleanliness throughout the operation is important, clean everything before you start taking it apart so nothing falls into either the injector or pump.
A toothbrush, WD40 or diesel followed by a burst of air is good but not absolutely necessary.

Remove the clamp holding the lines together, remove the nuts holding the line. Blow out the new line, install it, tighten the nut on the injector pump fairly tight, install the injector nut finger tight, then back it off a little, turn the engine over until fuel comes out the injector nut. If you've not broken the other injector line nuts loose, the engine may start. If it does, don't panic, just shut it down, tighten both nuts and start it again. It may run rough at first but should even out as the air is worked out of the system.

If it doesn't start, turn it over until you get a regular spurt of fuel out at the injector, then tighten both nuts and try again.

This is just a generic way of doing it, there are idiosyncrasies among various engines.

A 6 point line wrench, which looks like this



will help to avoid rounding off nuts. 17mm is a common injector nut size, make sure you use the correct size.

No need to crank down on it like Hercules, after it bottoms out probably only about a quarter turn or less is all that's needed...but obviously this is a variable value...

[theway]

Originally Posted by Techtool

Replacing the line is extremely easy if you have a new or good used in your possession. Just looking at the new line will clear up any questions. If you are ever stuck and can’t get a new line assembly it is possible to remove the line with the stripped nut, take it to a welding shop and get them to build up the nut again with silver solder and re-form it to a hex shape. Just remember that when you replace the line torque the nuts on both ends to about 22 foot pounds. That’s about what a 90 pound woman could do with a 6 inch wrench... or at least my 90 pound woman does

Thanks for the info...

Many engine repairs which seem easy often become difficult on the Pearson 323 because of the engine room size/location, one of only two cons that I’ve found.

I usually just get them really snug when I’ve had to bleed the engine, but I think the guy that took out the injectors for cleaning really cranked down on them...

[theway]

Originally Posted by jimbunyard

Pretty basic, cleanliness throughout the operation is important, clean everything before you start taking it apart so nothing falls into either the injector or pump.
A toothbrush, WD40 or diesel followed by a burst of air is good but not absolutely necessary.

Remove the clamp holding the lines together, remove the nuts holding the line. Blow out the new line, install it, tighten the nut on the injector pump fairly tight, install the injector nut finger tight, then back it off a little, turn the engine over until fuel comes out the injector nut. If you've not broken the other injector line nuts loose, the engine may start. If it does, don't panic, just shut it down, tighten both nuts and start it again. It may run rough at first but should even out as the air is worked out of the system.

If it doesn't start, turn it over until you get a regular spurt of fuel out at the injector, then tighten both nuts and try again.

This is just a generic way of doing it, there are idiosyncrasies among various engines.

A 6 point line wrench, which looks like this



will help to avoid rounding off nuts. 17mm is a common injector nut size, make sure you use the correct size.

No need to crank down on it like Hercules, after it bottoms out probably only about a quarter turn or less is all that's needed...but obviously this is a variable value...

Thank you, very helpful.

I finally got it loose, after removing the fuel return so I can get more rotation and access to the nut, which still has one or two good sides. And yup, 17mm is the size.

Those wrenches look like they might solve the problem altogether, or at least give me another year or two from the current nut. I kept thinking I need a “Crescent wrench”, which I think covers 4 side, but 6 is amazing.

Maybe I’ll get a new one line and take it as a spare. I think the guy that cleaned my injectors cranked down on it with one of these good wrenches... but then again I’m not completely sure he had to touch these in his process, but it was tighter than I can imagine I’d ever tight something like that... maybe I just want someone to blame ;-)

Thanks again.

[DougR]

If you do end up replacing the line, make sure you replace the vibration damper clamps (blue in the drawing) in the same location that they were originally. The purpose of the clamps is to prevent the high pressure lines from vibrating, fatiguing and cracking. Engine manufacturers go to great lengths to find the best place to locate the clamps to avoid problems.

DougR