If the fuel is "dirty" could you filter somehow before using in any engine. I cannot imagine that dirty fuel would be good for the engine. It could probably be run through a cheesecloth and brita filter to clean it up? Just a guess. LOL
As a side note, my Grandfather would use fresh Kerosene to flush his lawn mower engines. He would drain the oil, remove the plug wires, add some kerosene to the oil and crank it over for second or two. He would do this two or three times until what came out of the engine was clean and clear. Then he would replace the filter and fill with clean oil. From my recollection, all of his engines went hundreds of hours without any issues.