Like everyone else I too have had problems with the line feed on this model (TB525CS). Specifically, after a couple of bumps the line seems to come out all at once. Being of a curious nature I disassembled the head completely and discovered the root of the problem. There is a spring loaded mechanism that is supposed to regulate how much string is released in a bump. What happens is this mechanism starts to stick due to a poor design involving a circlip and a weak spring.Long story short after putting a washer under the circlip and adding a much stronger spring at the base this is actually a very capable head. I never had any problems with the engine so I am pretty happy now. I still have to give this product one star because no one should have to go through this much work to make a product function like it is supposed to.