Speaking of heat, it is a good idea to heat the engine with a hot air gun before you flip it over. this expands the cylinder before you try to start it. Not absoulutely necissary, but it reduces the stress on the piston and crome cylinder for those first few seconds. It is a procedure recomended by the best minds in the buisness. i don't even flip my prop untill the engine is hot.

Also a good idea to add some castor to your first gallon of fuel. I use Byron 10% nitro, 18% Castor/sinthetic blend and add about 4 ounces of castor. the sinthetics can break down with engine heat, but the castor does not.

Run it on the ground for a couple tanks, then fly it. be sure to keep the mix rich (you should see a exhaust mist when you are flying.

The OS engine comes with a manual which talks about break in. have you read it? if not do.

Break in is easy and somewhat forgiving if you don't do it exactly right. just be sure you don't run it lean, that's a killer, especially for a new engine.