Sorry I missed this before. I have a tach hooked up to ensure I don't over rev it. The prop itself if pitched to prevent overspeeding. I'm only going to run it up to 2800 RPM (via adjusting pitch blocks, as needed); I think my book says it is rated to 3600 RPM, same as any other small engine.I know that these engines aren't made for high revs but are you going to put a rev limiter on it? What is the rev limit for these engines? It's a nice quiet setup that's for sure!