Cleaner mower, speedboat engines ordered Gasoline-powered lawnmowers that are a big cause of summertime air pollution will have to be dramatically cleaner under rules issued Thursday by the Environmental Protection Agency. The long-awaited regulation requires a 35 percent reduction in emissions from new lawn and garden equipment beginning in 2011. Big emission reductions are also required for speedboats and other recreational watercraft, beginning in 2010. EPA said approximately 190 million gallons of gasoline will be saved each year when the rules take effect, and more than 300 premature deaths prevented annually....