So I started taking the carb apart to find out what went wrong. Easy stuff first with the removal of the throttle arm and then undoing the over size bolt which is holding down the pump cover and releases the barrel. When I pulled the barrel out the needle stayed in the carb! Curious as I am I pulled the needle out and the spring that helps keep the barrel tight. Nothing wrong with the needle it is a very simple design and the two o rings were in good condition. So I placed the needle back into the barrel and screwed it back in. The threads caught nicely and everything went back together like new. Now I am really curious as to why it dropped out of the thread before stopping? How can I gently wind in the needle until it stops and then wind out the required 5 turns? This will be interesting and will need further investigation, no doubt there is a simple explanation and I look forward to finding out what it is