guys i posted before that the flywheel cand be used to make the engine smoother at idle.
rag the everytime the piston goes down is not a power stroke like you said only on a 2stroke. it fires on the 3 stroke of compresion then on that down motion is power stroke in a four stroke engine.
also an engine will not stall with a light flywheel because that is where ignition timing and idle speed comes into place.
for example in a vw beetle drag motor that runs 11's in the quarter mile we would use a 9 lbs flywheel and a factory wheel was around 18 lbs the reason we didnt use a heavier fly wheel is because the car was extreemly light at 1500 lbs and had 190 hspower it didnt need the extra flywheel wieght it was a 2.2 liter engine but when i dcreased the displacement to 1.8 liters i had to increase the flywheel wieght to make it launch harder. the wieght has nothing to do to increase compresion or power it makes all it does is smooth the engine out for better idle an for of the line drivability the engine does not need a flywheel to run guys its actually there to make it more drivable!but added benift we can tune it to make the egine behave different (feel different).