...so the saga continues

Fabian K - check your PM

I have tried richening up the bottom as you suggested, the problem is when I run it so rich, after straight when the excess rich mix clears out, the engine wants to run on, if I lower the idle speed then it loads up and wants to cut out.

Even though I ran the engine like this, after 10 min - lean bog, the top of the piston is very dark ( obviously hot) , yet the engine still runs cool

Damn strange...