TIMING

One of the essential factors in a internal combustion engine (Fuel, Air, Proper proportion of mixture, compression , Timing, spark ). When the piston is in the compression stroke , both valves must be closed. If one or more is open, the valve timing is out. Perhaps a timing belt or timing chain has jumped a tooth. If the spark does not arrive at the correct moment, the engine is out of time. If this ignition timing is only slightly off, the engine may run with less efficiency .