There's only one way that an air-cooled engine can overheat, and that is grass/debris impeding the airflow. Remove the blower cowling from the engine (procedure differs depending on what engine is fitted) and clean it out.
Plug gap is 25 thou (0.6MM), fuel is non-adjustable (apart from - possibly depending on engine - idle speed).
phil_saunders@bigfoot.com
Phil Saunders
June 2008