It continues to fascinates me how Lycoming still publishes this generic set of recommendations, despite the fact that an O320 is like a TIO541 only to the extent that they are flat engines and both burn Avgas. Not to mention how much hard data GAMI has produced that challenges many old tenets. For example, that 'leaned roughness is due to misfiring', when in fact it is due to unequal power pulses associated with different burn rates and mixture distribution. Anyone who has experienced a real missing cylinder knows how it shakes the whole plane, as opposed to leaning roughness. And do you think that maybe internal cylinder temps rise faster than 50 degrees per minute when you begin a takeoff? Now, I'm not suggesting that all these published directions are bunk. I'm just suggesting that it is also a good idea to balance other sources of current information along with the traditional ones.
