A K&B .40 weighs 15 Oz. with muffler. A Magnum .52 weights 15.7, an OS .56 weighs 14.8, and an OS .40 weighs 13.3 Oz. Sounds like the OS .40 is a good match. But I agree the $200+ price tag is a bit much for such a small engine. Perhaps when they do rebates, or a used engine.