[rppngears]

Well, from the whole camp fire analogy, I thought I understood it, but apparently that is not the correct reason. I understand the air/fuel ratio and the H2O example just fine. What I don't understand is if the same amount of heat is generated regardless of ratio, as long as the same amount of fuel is consumed, then why is it so bad for your engine to run lean or rich? Why does this generate the extra heat? After combustion you will be left over with either some oxygen or fuel molecules, but they will be removed from the chamber on the next stroke.