I have 2 OS 70 Surpass engines, and both have done many 100s of hours. I am extremely happy with their performance. I have several times decoked them and ground the valves in.
I want to purchase a replacement and my question is "What is the difference with the OS 70 Surpass mk11?" Do I buy one of these or another original one? I want to assume that the new mk11 is superior in performance, howevere the BHP figure of 1.1 is the same for both. I see that the mk11 has a new carb, is this where the difference is?