So I've taken the plunge and will be pulling my yanmar apart down to the cylinder head, grinding and reseating the valves and cleaning the scale out of the exhaust manifold and cylinder head cooling passages. I have the exhaust manifold off and can see plenty of it along with some carbon buildup. What would you use to clean out the passages, get what I can with a wire brush and flush with water or do something more drastic like muriatic acid?

[Linked Image]
[Linked Image]

Last edited by JBiermann; 04/10/15 02:02 PM.