btw, the Alpha comes with the Evo engine normally. If you have that engine, the needle valve will have a limiter on it, so while Aeronaut's advice is good in general, it doesn't quite apply to the Alpha. Just set it towards the rich limit of it's travel, and it should be fine.

There have been a few cases of the needle limiter on an Evo engine being set to a point that wouldn't allow it to run right, but it's rare, and I doubt it's the case here.