Proper way for throttle inputs

[RyanB]

Just would like to get some information about the correct way to give throttle inputs such as takeoff and changing power settings at altitude. I was at the airport yesterday and noticed a pilot was taking off in a 172 and he jammed the throttle forward very quick, does this hurt the engine? I understood you should push the throttle in about 3 seconds on takeoff as a smooth power input. Does jamming the throttle quickly on takeoff hurt the engine vs the comparison?

 

[Jim Logajan]

My aviation mentors have taught me that a part of flying well is being smooth and deliberate in all my actions.
It appears to me the fuel systems used on most aviation engines are not designed for rapid control movements.
I find joy in striving to be smooth and graceful.

I assume that the only thing in the fuel system being changed by the throttle in a carbureted engine is a butterfly valve. My understanding is that, except for mixture, all operation of the engine follows from only the valve position. Air/fuel flow volume would change no faster than the engine rotation can accelerate/decelerate to the amount allowed by the new valve position, since the motion of the engine pistons are the ultimate drivers of the throttle feedback loop.

I presume a fast change in the butterfly valve position would cause the cylinder whose intake stroke happens next to fire at much greater force, but I haven't worked out in my head yet how that might cause problems such as misses or misfires in either that cylinder or the other cylinders.