Many thanks for all your help. I have several things I can now try. I have lined the area of the fuz that could get burned with litho plate to protect the servo wires above so I am good to go with a few experiments. First of all I am going to change the glow plug as I think this might be old and maybe not have the element pulled out enough.

Sicklick you are correct I was talking about the on board regulating valve which one set is usually fixed in position. And yes I am using mixed gas

Bert