The absence of a flywheel in an internal combustion engine (ICE) can lead to operational instability, as the flywheel provides necessary inertia to smooth engine performance during the compression stage. While modern vehicles typically utilize smaller flywheels compared to older models like the 1920s John Deere tractor, the flywheel remains crucial for maintaining consistent engine operation. Without it, an engine may run until a cylinder fails to produce enough power, potentially causing the crankshaft to stop. In cars, removing the flywheel could allow momentum to keep the crankshaft turning temporarily, but this would ultimately lead to drivetrain damage from torque vibrations. Overall, while an ICE can function without a flywheel, it risks severe operational issues and mechanical failure.
. 
