I have recently bought a Honda 50 Hp from 97 the person who sold it told me that it originately was a 40 BF and that a Honda dealer had changed the carbs to the 50 Hp´s ones so that the motor has now 50 hp as this was the only difference between the modells. the motor starts and runs fine in higher valves but at low valves and idle it is too low and rough like my old 2-stroke johnson, it almost seems like it runs only on 2 cylinders at low rev.<br />Can it be a problem with this upgrade which is probably some years ago, or could it be simple adjustment work like synchronizing? is it really so easy to upgrade the 40 to the 50 hp? I really hope I didn´t make a mistake to buy this motor.<br />Thank you for your help