A Rossi 91 2 Stroke engine will have more power than a YS 120 4 Stroke.
Really? So, we could put an 18x6 prop on that Rossi, and have it turn more RPM than the YS would? No way. Don't be misled by advertised horespower claims. Torque is what turns the prop, and a YS 120 will eat a Rossi 91 when it comes to torque.