medic976,

These are rear carb rear exhaust 31cc -- that makes them Ryobi. They are Yard Machines, owned by MTD, which owns the Ryobi license for trimmers. If these are the newer models, they will have a fan shroud that's integrally cast onto the crankcase, unlike the earlier models that were bolted on and easy to remove. You can still convert these, but it will take some sawing/grinding or milling to get them pared down. If these are recent models they will also probably be twin-ring units (good) but may have a single-needle carb (bad). But why pay 59.99? I just checked HF and the ones shown below were $49.99. Go buy!!!


http://www.harborfreight.com/cpi/cta...emnumber=55008

http://www.harborfreight.com/cpi/cta...emnumber=51584