Injector re-install

[Tim Mills]

After I'm ready to reinstall my injectors, Yanmar 3GM30, do I need to remove and or replace the copper cover and front and rear chambers and chamber gaskets, that are, I assume, under the injectors?

I haven't tried to pull those out of the head......yet.

 

[LeslieTroyer]

Yes they are one use parts unless you re-anneal them and re flatten.

Les

 

[Tim Mills]

Well, I spoke too soon. I went back to the boat and was able to slide the front and rear chambers out Looks like I need to only replace the copper washers, insulator and O ring for each and clean the chambers.

 

[heritage]

I had my 2gm20 injectors serviced and I replaced the aluminum/fiber gasket below the injectors but couldn't get the pre-combustion chamber things out. I gave up and the motor has run well now for 2 years. I have read that some have had to remove the head to do a proper removal of the chambers. Hopefully yours will come out easily, if not, I would leave them in.

 

[Tim Mills]

Mine came out quite easily. The more I play with this engine the more I am impressed in how well it is made

 

[Charles Erwin]

The order is - from bottom to top - copper seal, pre-combustion chamber, copper seal, insulator, seal,cover, injector with O-ring. The O-ring keeps the the moisture out of the injector bore - see to it you use new ones in each bore. See shop Manual 2-11.

Tim's experience is unusual. Unlikely you will be able to get the first two (seal and pre-combustion chamber) out of the bore. If you do you are very lucky indeed. As to the next in the stack - seal, insulator, and the insulator seal and cover - be aware the last two (the insulator, insulator seal, and cover) will look like one thing because they are well smashed together.

The short of it is - do not expect the very bottom items (copper seal and the pre-cumbustion chamber) can be removed - unless you remove the head and press these chambers out from the piston side.

So replace what you can remove. In any case the insulator and the pre-cumbustion chamber are the only things you will reuse. The rest need be replaced with new (costs pennies by the way.)

When installing the parts use Antiseize Nickel to coat the parts - far better than copper or aluminum versions in this particular case.

14 ft/lbs evenly on the injector hold down retainer nuts - no more.

All three bores get the same treatment.

Manual here:

https://sbo.sailboatowners.com/downloads/3GM_Engine_Service_Manual.pdf

Charles

 

[Tim Mills]

You guys are awesome. thanks for the input. Yes. I guess I'm lucky. Everything came out fairly easily. Will get parts from Toadmarine.

 

[ggrizzard]

Thank you Charles as well.

 

[Tim Mills]

Charles:
You are correct. The seals and insulator parts are all mashed together and it was difficult to even tell they are separate parts.

 

[Charles Erwin]

Tim - a comment

Since you are in the region - consider replacement of the goose neck (mixing elbow) in photo #1. Here is a lead. I have used these - and they are quite reliable.

https://hdimarine.net/product-category/yanmar/

In any case a clean mixing elbow (factory or HDI) is the objective. The problem is that most folks don't make an honest analysis of a degraded (strangled) mixing elbow.

Otherwise your reinstall looks spiffy - and that is worth plenty in my estimate.

Charles

 

[jmce1587]

Guys, a quick question. How often should you pull the injectors for cleaning/servicing? I have a yanmar 2GM20F in my mid 80s Hunter and have owned the boat for 10 years. I haven’t personally put a lot of hours on it. It is the original engine and don’t have any info from previous owners. I have replaced the mixing elbow about 2 years back out of precaution and again not a lot of engine hours since replacing. Engine is running well (touch wood so I don’t jinx myself!) I am planning a trip down the ICW from Tx to Ms Gulf Coast in a few months and this will require quite a bit of motoring/motor sailing. Thanks in advance for comments/input, Jerry

 

[Tim Mills]

Tim - a comment

Since you are in the region - consider replacement of the goose neck (mixing elbow) in photo #1. Here is a lead. I have used these - and they are quite reliable.

https://hdimarine.net/product-category/yanmar/

In any case a clean mixing elbow (factory or HDI) is the objective. The problem is that most folks don't make an honest analysis of a degraded (strangled) mixing elbow.

Otherwise your reinstall looks spiffy - and that is worth plenty in my estimate.

Charles

Yes:
I have already ordered a stainless steel mixing elbow and exhaust manifold.

 

[Tim Mills]

Guys, a quick question. How often should you pull the injectors for cleaning/servicing? I have a yanmar 2GM20F in my mid 80s Hunter and have owned the boat for 10 years. I haven’t personally put a lot of hours on it. It is the original engine and don’t have any info from previous owners. I have replaced the mixing elbow about 2 years back out of precaution and again not a lot of engine hours since replacing. Engine is running well (touch wood so I don’t jinx myself!) I am planning a trip down the ICW from Tx to Ms Gulf Coast in a few months and this will require quite a bit of motoring/motor sailing. Thanks in advance for comments/input, Jerry

The reason I am doing mine is because I was getting a little more black smoke than normal and some hard starting.
I had a diesel shop recondition the injectors. They were tested and all failed pop tests. They have been reconditioned with new nozzles for $100 ea. I have also had the cooler boiled out, cleaned and tested to 20psi for $125. New stainless mixing elbow and exhaust manifold is another $300. The old mixing elbow was at least 1/2 blocked. Getting a new thermostat and fuel lift pump while I'm at it. I'm doing all this for the same reason as well. I want to do the ARC Delmarva rally next year and don't want to worry about having any engine issues when off shore. Cooler cover and elbow pics attached.