If a diesel engine runs out of fuel, the fuel lines fill with air. These fuel lines must be purged of the air and filled with diesel. Learn how to restart a diesel tractor after it has run out of fuel in this free video on tractor operation. Expert: John Ryan Contact: www.rcotractor.com Bio: John Ryan works for the family-owned RCO Tractor in Austin, Texas. The roots of the company date back to the mid 1900's and they provide Texans with farming and ranching equipment. Filmmaker: Mark Bullard