I suggest you get a full refund, and buy a different brand of trimmer.
The Black & Decker belt-drive trimmers (GL741 and GL720) are poorly designed: Drive belt failures seem to be common, and the plastic drive gear can melt. They are not built to last.
Caine's comments above seem to refer to a mower, and are not relevant to this GL741 trimmer.
BobW
September 2010