Diesel Yanmar Injector Copper Washer Replacement

Hello, I was wondering if anyone could help me here.

Basically, I recently purchased a Yanmar YM14 tractor mower which I knew had an issue. The engine wouldn't run properly due to a leaking injector which I thought would be a case of removing the old washer and installing a new one, however when I removed the injector I found the copper washer had been drilled into and is very stuck in place. This must have been an attempt to remove the washer.

I have attached a few photos. Does anyone know how I can go about removing this copper washer?

I look forward to a reply.

Kind Regards

If you can have someone help you all the better, carefully apply heat from torch to break it loose keeping torch several inches away & have a set of needle nose pliers handy to grab it when it breaks loose, let us know how it goes, thanks.

From what I can see in the picture it sure looks like someone made a big mess. Looks like they drilled right into the steel. I just have a feeling that heat is going to do it for you but at this point what do you have to loose. I am only going by a picture but it looks like the copper washer is made into a steel insert, is that insert replaceable? Do you have a parts picture break down? Is the copper washer replaceable?

If you can get it and plug the hole with something steel then nitric acid will dissolve the copper in no time flat without attacking the steel.
In reallity, the nitric will dissolve steel but it is very slow whereas the copper will dissolve by prefference and very quickly, even quicker if you warm ( not boil just warm ) the acid first.
Do it in the open and do not hang over the washer .
It will realise noxious brown fumes while it is working so just pour a little on, sit back & watch for the brown smoke to stop then pour a little more on.

The copper nitrate end probuct is quite toxic to plants & animals so suck it up with some rag and pop the rags into the garbage bin.

Thank you for all of your suggestions, I will attempt the task tomorrow and get back to you. The copper washer is a replaceable part and according to a parts diagram it is separate to the steel insert. It amazes me how stuck it is considering nothing is holding it in place.

Hard to tell from just a picture but it looks like the dinged up the steel insert some.

That is strange looking, like a group of sea lympets sitting in a circle. Do I see a little tab at 12 o clock? I imagine you tried lifting there? The prior suggestions are good. One which occurs to me is involved and with its own risks. I cannot tell what the steel center ring is and if it is part of the engine or washer. If part of engine it could serve as a pilot hole for a counter bore cutter which would remove the copper washer as shavings. Or if no center available a jig could be make and locked down somehow which could center on the washer for cutter removal (poss machine shop job).You are probably tryng to avoid head removal.

PS. I just looked at the engine pic. It looks like the adjacent cylinder has a banjo hex on it so the center ring must be threaded. Easier with threads for a pilot and cutter approach. And better yet does that head come off with just a couple bolts. If so an easier job at the machinist.