Originally Posted by Nano
I would check for air leaks, then check the rear case cover gasket to check that it's not leaking once the engine is warm (ie it runs ok for the first few minutes then develops the problem). The new needle holder (which you can get for free) helps carb setup.
For the spring, it is just inserted in a groove so it could have come out.
I already fixed the spring
I found that one of the screws in the head was loose and so was one of the srcews in the rear case cover but it felt tight I Email Team Orion and ask them about the upgrade but I have not received any reply
And thanks for your help