hit and miss twin flywheel petrol engine engine made by nelson brothers little jumbo made at saginaw michigan america in 1911 these engines were regulated by a centrifugal governor so when it slowed down it would trigger a spark these engines never had a spark plug they had two points inside the combustion chamber they have an electric charge running through them they are touching when they move apart you get a spark which ignites the compressed air fuel mixture to see more videos click link Motorcycles and steam engines - YouTube