Yanmar 3GM30F - Injection Nozzles

[Scott T-Bird]

Related to my other post, I found that in removing the fuel lines I also had to take off the retainers of the injection nozzles in order to get wrenches on the fuel line nuts. In the process, I simply removed all three nozzles along with the lines.

The manual says that disassembled parts must be cleaned with fuel oil and carbon has to be removed from the end of the nozzle body and the fitting section of the nozzle nut. I don't want to disassemble, but since I'm almost there, should I? Of course I'm reading about how the parts can't be mixed among the nozzles.

How do these look?

I'm also worried about exposing these openings to dirt & debris cause the engine has a lot of that right now. It's difficult to clean it without getting these parts out of the way first. It looks like the 2 openings on the right have fuel pooling above the opening while the one on the left looks dry. I'm tempted to wipe it clean if I can but I'm afraid to do damage, too. There seemed to be a lot of gunk surrounding the body before I lifted it out and it dropped in.

Is it worthwhile to take the nozzles someplace to have the spray condition checked? The manual shows what the spray should and should not look like. Is it worthwhile to simply replace the whole nozzle injection assemblies? Do they cost a lot?

 

[Michael Davis]

Now that they are out I’d have them checked ( not very expensive ) rather than replaced ( very expensive). The copper crush washers need to be replaced however.

 

[jon hansen]

had all my injectors cleaned/rebuilt last fall. diesel specialists, green bay.
the copper like washers you removed from the top are to never be reused. in a pinch you can heat the washers red hot with a torch. best to replace. it was not cheap to have my injectors rebuilt.
my perkins from the 60's, the parts are becoming harder to replace.

 

[jon hansen]

the 'banjo bolts' at the top, tighten only to specks. do not over tighten

 

[Scott T-Bird]

Now that they are out I’d have them checked ( not very expensive ) rather than replaced ( very expensive). The copper crush washers need to be replaced however.

Those are the washers in the picture? I was wondering if there is a reason why I found 2 washers at 2 injectors and just one washer at the third. Also does it matter which location, because I'm not sure which one just had one washer. It seems like one would be sufficient ... they were found at the bleeder screws. Is their only purpose to prevent leaking?

 

[jon hansen]

having the fuel system clean and leak free makes for a happy engine.

 

[Scott T-Bird]

the 'banjo bolts' at the top, tighten only to specks. do not over tighten

Yes, the manual calls out the torque and I have a torque wrench.

 

[Michael Davis]

The copper washers seal the joint. Should be two on each banjo bolt. The spec. torque crushes the copper to provide the seal. One below the bolt head and one between the parts being sealed.

 

[jon hansen]

scott, the banjo bolts at the top are for the return fuel feed. they are not to be used to bleed the system ever. on my old perkins anyway

if loosened, new washers used, every time. i bleed by loosening the fitting on the fuel line entering the injector. again, on my old perkins

 

[Michael Davis]

scott, the banjo bolts at the top are for the return fuel feed. they are not to be used to bleed the system ever. on my old perkins anyway
Same on mine and the old Universal. If you break the seal you need to replace them.

 

[Michael Davis]

Scott are those banjo bolts out of the top of your injectors? Then just one washer, maybe. The connection to the high pressure pump has two on my engine. I love my service manual. If you don’t have one down load, beg, borrow or steal one.

 

[Scott T-Bird]

The copper washers seal the joint. Should be two on each banjo bolt. The spec. torque crushes the copper to provide the seal. One below the bolt head and one between the parts being sealed.

Yes, I forgot about the return lines. Perhaps I lost one, or it's still stuck on the return feed.

 

[Scott T-Bird]

scott, the banjo bolts at the top are for the return fuel feed. they are not to be used to bleed the system ever. on my old perkins anyway

if loosened, new washers used, every time. i bleed by loosening the fitting on the fuel line entering the injector. again, on my old perkins

yep ...

 

[Scott T-Bird]

scott, the banjo bolts at the top are for the return fuel feed. they are not to be used to bleed the system ever. on my old perkins anyway

if loosened, new washers used, every time. i bleed by loosening the fitting on the fuel line entering the injector. again, on my old perkins

Are they just brass washers? I might have a size detailed in the manual, otherwise, I suppose I'll just find a source to match.

Duh ... copper!

 

[Michael Davis]

Not brass. They are copper, made to compress and seal.

 

[jon hansen]

they are copper crush washers. any dealer will have them i'm sure

and spares are nice to have aboard.

 

[Whatfiero1]

Take to industrial diesel shop they will test. I paid $50 each test and that $ went towards payment for rebuild. and rebuild included all crush washers injector washers to reinstall

 

[dmax]

Regarding cleaning the engine: I would clean around the injector holes with a Qtip and get some bolts the size of the injectors and screw them into the holes to seal them - you don't want that crud in your engine. Then you can finish the clean-up. Looks like someone spilled some oil when doing an oil change as there's oil in all the low spots.

 

[tfox2069]

This is an interesting question I'll follow for the experience of others. I paid $350 to have three 3ym30 injectors rebuilt this year at a local diesel shop used by the marine mechanic shop at our marina. That felt like a lot of money for that job, but I had them out and thought "why not". They weren't particularly dirty, nor was there any indication of issues - the removal was incidental to something else.

Afterward I looked online to see what NEW injectors would cost, and I was stunned and confused. It looked like I could buy brand new ones for as cheaply as $35 each (knockoffs on E-bay), and $212 EACH for an OEM injector from an authorized Yanmar parts dealer. I know folks will say "why risk an important part of your engine on cheap parts with unknown provenance". Fair enough. A cheap non-OEM impeller can sure cause no end of problems, whereas the OEM version will be dependable for one or more seasons if not run dry. So I just don't know enough to say what the differences are. I do know that barring any shoddy work by the diesel shop or my reinstall these injectors are unlikely to need any more attention while I own the boat. Buy once, cry once.

However, I would be interested in the experience of others with non-OEM injectors.

And the OP is right to be concerned about grunge getting into the injector holes. Def plug those up and then vacuum them clean, and then stuff a clean rag in there to keep it clean. You ARE supposed to replace ALL copper washers. But I couldn't get a couple of the crush washers to come out of the injector hole - even after trying with a pick. I talked to a mechanic and he said that as long as I didn't damage the washer I could reinstall the injector, torque, and then start the motor. If I get no fuel leakage, it successfully resealed. If I DO have leakage I'd need to pull that injector and figure out how to remove the copper washer. He said that was very common. Would love to hear any tricks for getting stubborn crush washers safely out of the injector hole. I saw one video where a Mercedes diesel mechanic made a special tool to do it, but didn't sell the tool. It is a common problem with diesels, apparently. He REALLY had to haul on one to get it out of an old Mercedes motor. It made me cringe. And he had lots of room to work.

 

[justsomeguy]

I have a torque wrench.

You may also need (a) crowfoot wrench(es).