RE: Problem with needle valve
Barkai,
I have seen this once, on one of my customer's engines.
He used a Dremel tool to grind the ends of the spring flat, so the spring presses against the nut and the needle handle surface, with better contact. He also used a length of Teflon pipe tape, to make the needle thread-on with a little effort.
I will send you a PM, later this evening, with details that will enable you to contact him.