(Reuters) - American Daniel Summerhays fired a nine-under-par 62 to grab a two-stroke lead over Canadian David Hearn heading into Sunday's final round of the John Deere Classic in Silvis, Illinois. Defending champion Zach Johnson, the 2007 Masters winner and overnight co-leader, was lurking just off the pace another shot back at 16-under-par 197 after posting 67 at TPC Deere Run in the third round on Saturday. ... More...