Like Fish mentioned, try a different brand of line. Check to see what size best fits your trimmer. Husqvarna Titanium Force & Oregon Magnum Gatorline are some good weld resistant lines.
I put an Autocut C26-2 on my FS-91r and it's a breeze to use. I put about 2 arms length of .095" Husky Titanium Pro on it and have never had any feeding issues.
I've also used .105" Xp Pro line with no problems.