Yanmar Injectors

[richardabeattie]

Suggest you service the injectors!

 

[Gottenhimfella]

For those that have asked why I'm removing injectors for servicing here goes:-

Engine exhaust has been smokey (lightish grey) for last couple of months. No engine oil being used and exhaust smells of diesel (noticeable when motoring downwind).

Dried out on slip. Cleaned fouling from prop & hull in case engine was being overloaded. Boat went a bit faster but no change to smoking exhaust.

Intake air filter/silencer is new & clean.

Checked / reset valve clearances.

Compression good.

Exhaust elbow and first section of exhaust hose renewed a year ago. Plenty of cooling water coming though.

Running out of things to check so thought injectors would be next on the diminishing list. They haven't been out for 15 years.

Haven't checked the return hose from injectors to tank yet but can't see how that would be blocked.

Any other suggestions?

We ran a 1GM20 for 25 years and in that time we needed to replace the injectors twice due to smoke in the exhaust, enough to make the transom quite dirty in a matter of days.

Pitting on the needle both times - supposedly from water in the fuel -- but we had very effective separators - an isolation tank in the breather line with swan necks and a porous plastic filter - made of see-thru plastic and visible from the filler though a hatch into the lazarette, so it doubles as a visible overflow tank if you don't stop filling soon enough. Deep sumps at the tank below the draw-off points, and then a settlement unit before the primary filter: we've never seen any water in the latter - but the pitting was visible at fairly low magnification so it was not a con job.

 

[Onewatt77]

I have decided to have the injectors on my Yanmar 2GM20 serviced. Can some one please advise what seals need to be replaced and which can be re-used:
a) My manual doesn't seem to show a washer under the injector where it screws into the cylinder head though I believe there is a copper washer there (Renew I presume).
b) There appears to be Two Sealing Washers for each injector at the fuel return pipe connection (re-use?).
c) I won't be dismantling the injectors myself but should the Packing between the Nozzle Spring Nut and the Nozzle Holder Body be renewed?

Hi Steve

what was the outcome of this if you don’t mind me asking ? I currently have the injectors out of my 2gm20 for servicing and I’m looking at the same questions of what to replace as you had

Mike

 

[sailoppopotamus]

I am also interested in this. I want to have the injectors serviced but cannot risk having to remove the head. I'm worried that the old copper washers might not seal properly when I reinstalling, assuming I manage to get the injectors out in the first place.

@Onewatt77 Out of curiosity, is there a definite problem you are trying to address with the engine, or is this just preventative maintenance?

 

[jwfrary]

Probobly the lower pre combustion chamber won't easily come out, the top part however usually does without any real effort.

Theres 1 graphite washer/gasket 2 copper rings if you include the lower one, a copper heatshield (thin copper washer just the tip of the injector protrudes)

The lower ring probobly will not be needed assuming the lower chamber isn't bing removed.

In a pinch you can anneal the old washers, but the graphite seal and thin heatshield are not reusable

 

[Onewatt77]

I am also interested in this. I want to have the injectors serviced but cannot risk having to remove the head. I'm worried that the old copper washers might not seal properly when I reinstalling, assuming I manage to get the injectors out in the first place.

@Onewatt77 Out of curiosity, is there a definite problem you are trying to address with the engine, or is this just preventative maintenance?

I had engine running issues and isolated it to the injectors , I took them out and took them to a specialist who has confirmed they were in a bad way, they are currently refurbishing them and my attention is now turning to the refiting process , I’m worried what I will or won’t be able to get out now after reading all the comments

 

[fredrussell]

My 30 year old 3gm30 is on its original injectors. The engine smokes a bit above 2.5k rpm and I suspect cleaning the injectors wouldn’t hurt after all this time. However, I’m a sort of ‘if it ain’t broke…’ type of person, ESPECIALLY with old engines so until it becomes a problem to start engine, it can enjoy its twenty Marlboro a day.

 

[Caladh]

If you anneal the copper washers they are usually re-usable.

Servicing on such simple injectors is no mor than checking pressure and pattern - best done by a qualified diesel injection shop. Remarkably few and far between.

…and they should give you new seals for re-installation

 

[dansaskip]

Thought this might help - an exploded diagram of gaskets, washers etc