Generally, when you run for a second then stop, it means that what little fuel there was in the engine is burning up and not being replaced. This means lean. You might try moving your idle adjustment to a richer setting. You can also try a drop or two of fuel into the intake to see if this extends your short run. If it does, the try the richer idle setting.

Also, when you start the engine, be sure that your fuel line from the tank to the engine is full of fuel.