How do you adjust ignition timing in gas engine?

To adjust ignition timing in a gas engine, you typically need to access the timing adjustment mechanism, which may involve loosening the distributor hold-down bolt if the engine uses a distributor. You can then rotate the distributor slightly to advance or retard the timing, usually measured in degrees. For engines with electronic ignition, adjustments may be made using a scan tool or by resetting the engine control unit (ECU). Always consult the vehicle's service manual for the specific procedure and timing specifications.