Each manufacture has a bit different way to break in an engine, they went to all the time and trouble to design the engine so they have broken in a few and know how they want it done. For two stroke engines I use SK designed by the engineers at Super Craft and made in China for them. The engineers came up with there way to break in the engine and what props to use. This is one of the only engines I know that have a different break in then the instructions that come with the engine.