I installed a new line speed spool cartridge a new bump nob. My line is fed appropriately but I can't get the line to turn in order to cut the weeds. Then, I took everything off again and started the weed eater,and found that the shaft doesn't turn. What could be the issue? Please help with possible solutions. Thanks

Make sure the steel cable that runs up the weed eater isent broken or not all the way up in the proper place.You should be able to pull the cable out to see if its broken,some models have a locking nut that holds the cable in place some don't.

Pete is right on both counts, most likely not slid all the way back into the engine.

Thank you ballengerb :), isent great to help people out.