When I purchased my new Stihl FS100R I had the same trouble. Being used to 2 stroke trimmers that I could feather the throttle, I had not problems using the trimmer to edge curbings and such with. However, the new 4 mix motor of the Stihl, I found it difficult if not impossible to feather the trigger and this was causing string breaks since I was trying to run it a WOT. I found that if I would lock the trigger like when starting that a comfortable RPM for edging was acheived. This helped tremendously with the line breakage. Also being sure that you're not to close to your work is very helpful. I also found out going backwards is better than forwards but this sometimes causes mis-steps which can cause embarrassing moments ( from experience ). It did help me in getting a "feel" for the new trimmer. My Husqvarna 324LDx is my favorite trimmer and the easiest head to rewind, I never had the line break trouble with it. Hope this helps.
2001 Dodge Ram 2500 Turbo Diesel
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