Ответ на "Why is the end of the shaft, and the oil, overheating?"Also check there is no weeds or extra trimmer line wrapped around the shaft causing friction and heat to build up. Check (WITH MOTOR OFF) if the spool is easy to turn and free of debris buildup. Remove spool to check for excess movement from the shaft as said previously. This may be as simple as replacing the shaft bushing or bearing depending on which model you have.