Three people suffered minor injuries when a go-kart operated by the Shriners went out of control and rode onto a sidewalk along the Maine Lobster Festival parade route Satruday, police said. Rockland Deputy Police Chief Wally Tower said a 43-year-old man and a 9-year-old boy were treated at the scene, and a 79-year-old woman was treated and released from a hospital. Tower said the cause of the accident is under investigation.