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Q What is the cause of a petrol engine tending to run-on after the ignition has been switched off?
17th March 1967, Page 155
17th March 1967
Page 155
Page 155, 17th March 1967
— Q
What is the cause of a petrol engine tending to run-on after the ignition has been switched off?
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AThis phenomenon is associated with
surface ignition which can cause knock when the engine is running. An overheated sparking plug, exhaust valve or deposits of combustion products can cause the mixture to ignite with the ignition switched off and the engine will run-on. This may be accompanied by detonation that, in an extreme case, can damage the working parts of the engine. Surface ignition when the engine is running can cause a phenomenon known as "wild ping" if it is combined with a tendency to knock resulting from compression ignition of the end gas.