ORIGINAL: Mavi91
I took Jen's advice instead and so, about a gallon and a half later, this engine (that was well used when I converted it) is still going strong. I will admit to needing to shovel out the carbon now and then, but I'm guessing that olive oil in the mix will cure that problem.
From PAW model dieselengine factory: NEVER dismantle an engine in order to "decarbonise" it. Excess carbon is ejected by the engine automatically as it accumulates.
I has used motoroil, castoroil and never experienced the engine has been damaged by carbon.
Mostly of carbon came from burned kerosene/autodiesel and a very little part from lube oil. You can see there are much oil out of exhaustport/muffler because the engine are running colder than glowplug engine.