If you don't run your O.S. Max .46 LA at full throttle during the breakin process, you won't get it broken in and you'll have an engine that will likely have a much-reduced service life. The main caveat is to not run it in "four-cycle" mode.

You can always tell if you are rich of peak by the fact that a quick pinch of the fuel line will give you a jump in RPM.

Please check the O.S. FAQ page:

http://www.osengines.com/faq/product-faq.html