Can anyone give me information for obtaining an owner's manual for a Sears Craftsman gas string trimmer. Model # 316.798221. It has a straight shaft, dual cutting line, bump head. It has a 2 cycle 31cc engine. Sears parts says the manual is unavailable. I'm guessing this trimmer is around 8 years old and in like new condition. Does anyone know who made this for Sears. I can contact them about a manual.