IDG · fire the spark at the top of compression — learn the engine cycle
RPM0
STROKE—
FIRES0
REDLINE6000
Fire as the piston nears the top of the COMPRESSION stroke. Good timing adds RPM; misfires bleed it.
A 4-stroke engine repeats: Intake → Compression → Power → Exhaust. It only makes power if the spark fires just before the piston reaches the top on compression. Keep the timing to spin it up to the redline — miss and it stalls.