When I go to use my strimmer it continually breaks the string at the bobbin hole.I have tried rethreading it and used alternative ways but it starts ok and then when I go to cut the line breaks.Why??
Could be a damaged eyelet causing a pinchpoint on the trimmer line, a missing spring or poor quality trimmer line.
Buy a new spool cover kit from ALM Manufacturing
part number ALM BD030
http://www.almmanufacturing.com/index.php/products/garden-machine-parts/grass-trimmers/black-&-decker-grass-trimmers/item/177-alm-bd030-spool-housing
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix grass trimmers.