[Frankfurder]

Having removed the exhaust elbow on my 1gm I have more carbon buildup in the exhaust manifold/port than in the elbow. Seeking advice on the best way to remove carbon without getting dust/debris in the cylinder?

I,have read to verify that valves are closed, not sure how to, do that , but it looks like the valve cover must be removed. Don’t think I want to,go,that far.

 

[Capt Len]

Seems to me that both valves are closed on the compression stroke. Turn by hand until you feel the squeeze. This works when there's only one cylinder in question .

 

[JimInPB]

Valves closed & piston at top dead center is my first choice.

 

[sesmith]

There's only one nut and seal washer that holds the valve cover on a 1 gm10. 5 minutes will have it off. It's probably due for a valve adjustment anyway.

 

[partman]

I will also need support for Yanmar parts.

 

[Minnewaska]

If it’s just a light coating of soot, I’d ignore it. Totally normal and it will return shortly after going through all the effort. If it’s caked on and pieces are flaking off, that you might want to address, along with why the engine has such incomplete burn. Diesels are all sooty, however.

 

[AhoyhoyMarine]

If you think the valves are not closing, well, you could do a compression test, but, if you have ever tried to start a 1GM with poor compression, you'd know that you have almost no chance. Remove the head and take it to a machine shop to have it tested, valves reseated and resealed. This will solve two problems you have. One, your build up is a result of either oil or water mixing with the carbon from the exhaust. Two, if the head is okay, soaking the head will clean it without damaging it, unlike using files and drill bits, screwdrivers or other tools which people try to solve their own problems with. It feels like you might try and solve your own problem, but you should solve the source of your problem too. It's just money!