I haven been testing a couple of different props on my BF250. I would like to know what RPMs others are turning at WOT on their BF250?
The manual lists the BF250 WOT operating range as 5300-6300 rpm. This is the first large 4 stroke I have ever had. In the past with 2 strokes I have always propped to so that WOT RPMs are very close to the maximum allowed. I have seen online that peak horsepower is achieved at 5800 rpm. During my prop testing I have found this to be true. During testing most of the props pull strongly up to 5800 rpm. After this point the increase in rpm is much slower. I have tested props that have peaked at 5900 and up to 6200 RPMs. I am just wondering if there is any benefit to trying an prop closer to 6300 rpm or whether being able to 5800-5900 rpm would be better. I got better cruising economy with the prop that only achieved 5900 rpm WOT. Which makes since as it is a larger diameter prop. I just want to make sure I am not overpropping the motor. Overpropping could could can cause unnecessary stress on motor I have also heard overpropping can lead to 4 strokes making oil.
The manual lists the BF250 WOT operating range as 5300-6300 rpm. This is the first large 4 stroke I have ever had. In the past with 2 strokes I have always propped to so that WOT RPMs are very close to the maximum allowed. I have seen online that peak horsepower is achieved at 5800 rpm. During my prop testing I have found this to be true. During testing most of the props pull strongly up to 5800 rpm. After this point the increase in rpm is much slower. I have tested props that have peaked at 5900 and up to 6200 RPMs. I am just wondering if there is any benefit to trying an prop closer to 6300 rpm or whether being able to 5800-5900 rpm would be better. I got better cruising economy with the prop that only achieved 5900 rpm WOT. Which makes since as it is a larger diameter prop. I just want to make sure I am not overpropping the motor. Overpropping could could can cause unnecessary stress on motor I have also heard overpropping can lead to 4 strokes making oil.