Hi Richard,
I don’t know if you have knuckled down and made yourself a pair of gauzes yet….I have found an old but unused one in a box of gaskets that came from the late Bruce Selous. I could send it to you to try on the side of the engine that is spitting back. If that is an instant cure you will be sure what the remedy is ! If not you could put it on the other side to make absolutely sure. I would like it back to keep as a pattern, but at least it will give you a confirmation of the problem, and also you will see just what gauge of gauze ( !! ) you should use when making them.
Brian
