In this view I have tried to illustrate the relative complexity required to implement dual-fuel running. The tractor would be started using petrol and a conventional choke. When fully warmed up, particularly the hot-spot between the exhaust and inlet manifolds, the change would be made to very low tax paraffin for the rest of the day’s work. It was important not to allow the engine to idle for too long as the hot-spot might cool and allow the engine to flood with excess paraffin.