2GM20F injector service success story

sailoppopotamus

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For over a year I'd been deliberating over removing the injectors of my Yanmar 2GM20F for cleaning/testing, but was always worried that something will go wrong. Last week I finally bit the bullet and went down to the boat, fully expecting the injectors to put up a fight. To my astonishment, after loosening the various bolts and pipe brackets, the injectors simply slid out. It was also very easy to get the various washers and heat shields out. I didn't attempt to remove the lower precombustion chamber. I saw no real reason to do so, and I didn't want to risk any damage to it. The copper washer that sits on top of it was trivial to remove, I just pulled it out using my finger.

None of the items I pulled out appeared to be reusable. The heat shield/insulator/washer had all fused into one lump. All in all, I needed the following spare parts from Yanmar:

(stuff that was in the injector bore)
2Χ 24341-000260 O-RING, 1AS26.0
2Χ 128275-11500 COVER, PROTECTOR
2Χ 128275-11490 INSULATOR
2Χ 128275-11410 CHAMBER, REAR
2Χ 124950-11450 GASKET, CHAMBER

(copper washers for the fuel return pipe assembly on top of the injectors)
4Χ 23414-080000 GASKET, 8X1.0

The exercise was not particulary cheap, all these little bits cost me nearly 100 euros, so I was rather grateful that my engine only has two cylinders. Injector cleaning/testing by a shop set me back another 40 euros for both. They checked out fine and didn't need rebuilding. I only have 300 hours on the engine during my ownership, but I suspect the injectors probably haven't been looked at in more than 1000 hours. The engine seems to run slightly smoother now, and the exhaust seems slightly cleaner, but it wasn't really smoking in the first place to be honest.

I'm posting this in the hope that it might be useful to fellow 2GM20F (and related engine) owners. In mosts of the posts I found online people have had a terribly hard time removing the injectors and all the little bits below them. I was probably lucky but found the whole process very easy. Not sure the gains justified the cost in the end, but I now sleep soundly at night knowing that my injectors are healthy and clean.
 

Halo

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Glad it worked out for you!

An old mechanic who worked for me used to say “ the fuel systems of diesels are best left severely alone “. Apart from filters that has always been my approach.
 

sailoppopotamus

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I can definitely see an argument for that, which is why I attempted this in January and not in July :ROFLMAO: Doesn't take much for this to go horribly wrong. But it did bother me somewhat that it was one of the very few maintenance items in the Yanmar manual that I hadn't addressed so far into my ownership. In all honesty I was hoping it would magically make the engine run smooth, but I'm getting to the point of accepting the two cylinder engine for what it is!
 

AntarcticPilot

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Glad it worked out for you!

An old mechanic who worked for me used to say “ the fuel systems of diesels are best left severely alone “. Apart from filters that has always been my approach.
That was the attitude of the engineer who taught our diesel engine course, too. He also stated that a) few things could go wrong with injectors or injector pumps that would cause the engine to stop running and b) unless there were symptoms such as black or blue smoke, poor starting or rough running, and every other cause had been eliminated, they were best left well alone.

He also emphasized that working on them was NOT a DIY job because of requirements for cleanliness and precise tolerances. Sending injectors or injector pumps to a specialist, as the OP did, is the right thing to do. As he was very gung-ho and hands-on for everything else, including turbochargers, it stood out that he was advising complete hands-off for the internal parts of injectors and their pumps.
 
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