RE: pros and cons of 2 and 4 stroke engines ?
RC - my first 4C engine was a Saito 72, used ... about 1.5 years old ... it would still tach about 10,400 RPM easily. A new one should be able to hit about 10,750. So you tell me how worn is the engine? Like all engines it needs Tender Loving Care!
When you fly 2C engines you will notice that your throttle is usually at 70% onwards to get the plane to pull well. That is because the power comes at higher RPMs with a 2C engine. When I first flew the 2C engine it was like a total difference, I had to learn to use throttle management differently. The power comes at about 45% to 80%, after 85% there was not much more difference in speed. But you know what is best? An electric brushless motor with good batteries! Totally linear throttle!!! I love EP.