Yanmar 3GM30F - Injection Nozzles

[mermike]

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

Don't do what I did and screw up the conversion between Newtons and inch-pounds.

 

[RoyS]

I would buy new ones from Yanmar. Keep the old ones for emergency spares. I purchased an injector tester and rebuilt mine. This is doable but it is much easier to buy new. I would not pay to have them rebuilt if I were you. Buy new.

 

[tfox2069]

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

If you do use crowfoot wrenches, make sure you look up the torque conversion tables.

 

[justsomeguy]

If you do use crowfoot wrenches, make sure you look up the torque conversion tables.

Because of the extension used? And the offset nature of the wrench?

 

[tfox2069]

Because of the extension used? And the offset nature of the wrench?

Certainly the offset - the table changes the torque settings depending on how far off center you are wrenching.

 

[RoyS]

You should not have removed the fuel lines. The ends opposite the injectors go into the delicate injector pump delivery valves. These delivery valves should not be disturbed or contaminated. The flanges that hold them in the injection pump must be torqued but not over-torqued. When you install the fuel lines you must hold the delivery valve flanges to keep them from turning. Absolutely no debris may enter the fuel delivery system anywhere. Think of this as surgery as opposed to a tire change.

 

[Scott T-Bird]

You should not have removed the fuel lines. The ends opposite the injectors go into the delicate injector pump delivery valves. These delivery valves should not be disturbed or contaminated. The flanges that hold them in the injection pump must be torqued but not over-torqued. When you install the fuel lines you must hold the delivery valve flanges to keep them from turning. Absolutely no debris may enter the fuel delivery system anywhere. Think of this as surgery as opposed to a tire change.

Well, in order to replace the gear case gasket, which is the objective, I had to remove the fuel lines. In any case, it's done now. I will be replacing the fuel lines just because I want to. I have removed the valve spring holder on the first one (I assume that is what you are calling the "delivery valve flange"). I also removed one delivery valve and the holder to inspect as the manual suggests. I think I will just replace it.

In my other post, I described how I needed to get a wrench on each holder to keep it from turning. They are so close together, it appears that I will need to remove the middle holder to get a wrench on the 3rd holder. I was able to get the fuel line removed without holding the last holder, but I suppose that I will need to take care to hold each individually when torqueing the fuel lines back on. That means the holders will have to be re-installed sequentially, right?

 

[Michael Davis]

That means the holders will have to be re-installed sequentially,

Last out, first in.

 

[Arsen]

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.

With the smoke issue at startup/warmup on my 3GM30F getting worse, I decided to try the cheap non-OEM nozzles ordered from ebay to see if it helps. Thinking was that worst case I'm out of $30. Before fitting them on injectors I noticed that the needle valve tip is different from Yanmar patented type semi-throttle, looks more like blunt "pintle" needle tip. Fit in the existing injector body just fine. Smoke didn't get any better - next I'm checking compression, and taking injectors for service after replacing the OEM nozzles back. The engine definetly sounded notably rougher than it was with the OEM injectors, especially at low RPMs. Bottom line - only buy these in a pinch if no better options available/affordable. Hope somebody will benefit from my experience.

 

[Ken13559]

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

Happy "wife" happy life

 

[Rick Webb]

You guys think boats are expensive?

We have to replace the injectors on our tractor, all three are bad. I almost choked when I saw that they were $1,000 each.