How do I clear oil/air bubble/dirt/debris from my engine?
The best method is to prime and pull the engine, this will reset your fuel:air mixture, it will force through any dirt or detritus and clear any airlocks. Your fuel acts like a solvent and will strip the carburetor and chamber of any oil.
The process involves removing the spark plug, pressing the primer bulb four times and pulling the starter cord once, repeat this process ten times. Leave the spark plug out for 30mins and refit and retry your start procedure.