Honda BF35A-BF45A Outboard Motors Shop Manual., Page 219Get this manual
2)Operation 1When the oil pressure switch or thermo switch detects the trouble signal, the comparator circuit compares the condenser discharged voltage curve of the slowing down engine speed standard voltage circuit with the engine speed voltage signal and detects whether the speed is above or below the specified speed
2Getting the signal from the comparator, the flame-out circuit turns ONIOFF the transistor (TR) and controls the thyrister
3The slowing down engine speed standard voltage stabilizes at the preset stable engine speed and flaming-out and firing are repeated at this stable engine speed4After the trouble to the oil pressure switch or thermo switch is removed and trouble signal stops, the unit alert system repeats the above and 2