I've been told it's a Poulan. I have a 21cc.

The Featherlite weedies are light. Mine weighs 36oz with steel muffler and CH ignition.

I've heard the 18cc, 21cc and 25cc are all the same case, just different cylinders and pistons. I'm thinking about buying a 25cc engine and dropping the head and cylinder on my 21cc crankcase. Does anyone know if the bolt pattern on the cylinders and cases is all the same? I'd rather have the punched out cylinder and bigger piston. Probably weigh the same or close enough to the same you wouldn't notice the difference.